Indole and benzomorpholine derivatives as modulators of metabotropic glutamate receptors

ABSTRACT

The present invention relates to novel compounds, in particular novel indole and benzomorpholine derivatives according to Formula (I) wherein all radicals are as defined in the application and claims. The compounds according to the invention are positive allosteric modulators of metabotropic receptors-subtype 2 (“mGluR2”) which are useful for the treatment or prevention of neurological and psychiatric disorders associated with glutamate dysfunction and diseases in which the mGluR2 subtype of metabotropic receptors is involved. In particular, such diseases are central nervous system disorders selected from the group of anxiety, schizophrenia, migraine, depression, and epilepsy. The invention is also directed to pharmaceutical compositions and processes to prepare such compounds and compositions, as well as to the use of such compounds for the prevention and treatment of such diseases in which mGluR2 is involved.

FIELD OF THE INVENTION

The present invention relates to novel indole and benzomorpholine derivatives which are positive allosteric modulators of the metabotropic glutamate receptor subtype 2 (“mGluR2”) and which are useful for the treatment or prevention of neurological and psychiatric disorders associated with glutamate dysfunction and diseases in which the mGluR2 subtype of metabotropic receptors is involved. The invention is also directed to pharmaceutical compositions comprising such compounds, to processes to prepare such compounds and compositions, and to the use of such compounds for the prevention or treatment of neurological and psychiatric disorders and diseases in which mGluR2 is involved.

BACKGROUND OF THE INVENTION

Glutamate is the major amino acid neurotransmitter in the mammalian central nervous system. Glutamate plays a major role in numerous physiological functions, such as learning and memory but also sensory perception, development of synaptic plasticity, motor control, respiration, and regulation of cardiovascular function. Furthermore, glutamate is at the centre of several different neurological and psychiatric diseases, where there is an imbalance in glutamatergic neurotransmission.

Glutamate mediates synaptic neurotransmission through the activation of ionotropic glutamate receptors channels (iGluRs), and the NMDA, AMPA and kainate receptors which are responsible for fast excitatory transmission.

In addition, glutamate activates metabotropic glutamate receptors (mGluRs) which have a more modulatory role that contributes to the fine-tuning of synaptic efficacy.

Glutamate activates the mGluRs through binding to the large extracellular amino-terminal domain of the receptor, herein called the orthosteric binding site. This binding induces a conformational change in the receptor, which results in the activation of the G-protein and intracellular signaling pathways.

The mGluR2 subtype is negatively coupled to adenylate cyclase via activation of Gαi-protein, and its activation leads to inhibition of glutamate release in the synapse. In the central nervous system (CNS), mGluR2 receptors are abundant mainly throughout cortex, thalamic regions, accessory olfactory bulb, hippocampus, amygdala, caudate-putamen and nucleus accumbens.

Activating mGluR2 was shown in clinical trials to be efficacious to treat anxiety disorders. In addition, activating mGluR2 in various animal models was shown to be efficacious, thus representing a potential novel therapeutic approach for the treatment of schizophrenia, epilepsy, addiction/drug dependence, Parkinson's disease, pain, sleep disorders and Huntington's disease.

To date, most of the available pharmacological tools targeting mGluRs are orthosteric ligands which activate several members of the family as they are structural analogs of glutamate.

A new avenue for developing selective compounds acting at mGluRs is to identify compounds that act through allosteric mechanisms, modulating the receptor by binding to a site different from the highly conserved orthosteric binding site.

Positive allosteric modulators of mGluRs have emerged recently as novel pharmacological entities offering this attractive alternative. Various compounds have been described as mGluR2 positive allosteric modulators. WO2007/104783 and WO2006/030032 (Addex & Janssen Pharmaceutica) describe respectively 3-cyano-pyridinone and pyridinone derivatives as mGluR2 positive allosteric modulators. None of the specifically disclosed compounds therein are structurally related to the compounds of the present invention.

It was demonstrated that such compounds do not activate the receptor by themselves. Rather, they enable the receptor to produce a maximal response to a concentration of glutamate, which by itself induces a minimal response. Mutational analysis has demonstrated unequivocally that the binding of mGluR2 positive allosteric modulators does not occur at the orthosteric site, but instead at an allosteric site situated within the seven transmembrane region of the receptor.

Animal data are suggesting that positive allosteric modulators of mGluR2 have effects in anxiety and psychosis models similar to those obtained with orthosteric agonists. Allosteric modulators of mGluR2 were shown to be active in fear-potentiated startle, and in stress-induced hyperthermia models of anxiety. Furthermore, such compounds were shown to be active in reversal of ketamine- or amphetamine-induced hyperlocomotion, and in reversal of amphetamine-induced disruption of prepulse inhibition of the acoustic startle effect models of schizophrenia (J. Pharmacol. Exp. Ther. 2006, 318, 173-185; Psychopharmacology 2005, 179, 271-283).

Recent animal studies further reveal that the selective positive allosteric modulator of metabotropic glutamate receptor subtype 2 biphenyl-indanone (BINA) blocks a hallucinogenic drug model of psychosis, supporting the strategy of targeting mGluR2 receptors for treating glutamatergic dysfunction in schizophrenia (Mol. Pharmacol. 2007, 72, 477-484).

Positive allosteric modulators enable potentiation of the glutamate response, but they have also been shown to potentiate the response to orthosteric mGluR2 agonists such as LY379268 or DCG-IV. These data provide evidence for yet another novel therapeutic approach to treat above mentioned neurological and psychiatric diseases involving mGluR2, which would use a combination of a positive allosteric modulator of mGluR2 together with an orthosteric agonist of mGluR2.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to compounds having metabotropic glutamate receptor 2 modulator activity, said compounds having the Formula (I)

and the stereochemically isomeric forms thereof, wherein R¹ is C₁₋₆alkyl; or C₁₋₃alkyl substituted with C₃₋₇cycloalkyl, halo, phenyl, or phenyl substituted with halo, trifluoromethyl or trifluoromethoxy; R² is halo, trifluoromethyl, C₁₋₃alkyl or cyclopropyl; R³ is hydrogen, halo or trifluoromethyl; n is 1 or 2;

X is —CH₂CH₂—O, —CH═CH—, or —CH₂CH₂—; Y is —O— or —CR⁴(OH)—;

R⁴ is hydrogen or C₁₋₃alkyl; and the pharmaceutically acceptable salts and solvates thereof.

In one embodiment, the invention relates to a compound according to Formula (I) or a stereochemically isomeric form thereof, wherein

R¹ is C₁₋₆alkyl; or C₁₋₃alkyl substituted with C₃₋₇cycloalkyl, phenyl, or phenyl substituted with halo, trifluoromethyl or trifluoromethoxy; R² is halo, trifluoromethyl, C₁₋₃alkyl or cyclopropyl; R³ is hydrogen, halo or trifluoromethyl; n is 1 or 2;

X is —CH₂CH₂—O, —CH═CH—, or —CH₂CH₂—; Y is —O— or —CR⁴(OH)—;

R⁴ is hydrogen or C₁₋₃alkyl; and the pharmaceutically acceptable salts and solvates thereof.

In one embodiment, the invention relates to a compound according to Formula (I) or a stereochemically isomeric form thereof, wherein

R¹ is C₁₋₆alkyl; or C₁₋₃alkyl substituted with C₃₋₇cycloalkyl or phenyl R² is halo, trifluoromethyl or cyclopropyl; R³ is hydrogen, halo or trifluoromethyl; n is 2;

X is —CH₂CH₂—O— or —CH═CH—; Y is —O— or —CR⁴(OH)—;

R⁴ is hydrogen or C₁₋₃alkyl; and the pharmaceutically acceptable salts and solvates thereof.

In one embodiment, the invention relates to a compound according to Formula (I) or a stereochemically isomeric form thereof, wherein

R¹ is 1-butyl, 2-methyl-1-propyl, 3-methyl-1-butyl, (cyclopropyl)methyl or 2-(cyclopropyl)-1-ethyl; R² is chloro, bromo, cyclopropyl or trifluoromethyl; R³ is hydrogen, chloro or trifluoromethyl; n is 2;

X is —CH₂CH₂—O— or —CH═CH—; Y is —O— or —CR⁴(OH)—;

R⁴ is hydrogen or C₁₋₃alkyl; or a pharmaceutically acceptable salt or solvate thereof.

In one embodiment, the invention relates to a compound according to Formula (I) or a stereochemically isomeric form thereof, wherein

R¹ is 1-butyl, 3-methyl-1-butyl or (cyclopropyl)methyl; R² is chloro; R³ is hydrogen; n is 2;

X is —CH₂CH₂—O— or —CH═CH—; Y is —O— or —CR⁴(OH)—;

R⁴ is hydrogen or methyl; or a pharmaceutically acceptable salt or solvate thereof.

In an embodiment of the present invention, interesting compounds of Formula (I) and the stereoisomeric forms thereof are selected from the group comprising

-   1-Butyl-3-chloro-4-[4-(tetrahydro-pyran-4-yl)-3,4-dihydro-2H-benzo[1,4]oxazin-7-yl]-1H-pyridin-2-one     (E1), -   trans-1-Butyl-3-chloro-4-[4-(4-hydroxy-cyclohexyl)-3,4-dihydro-2H-benzo[1,4]oxazin-7-yl]-1H-pyridin-2-one     (E2), -   trans-1-Butyl-3-chloro-4-[1-(4-hydroxy-cyclohexyl)-1H-indol-5-yl]-1H-pyridin-2-one     (E3), -   cis-1-Butyl-3-chloro-4-[1-(4-hydroxy-cyclohexyl)-1H-indol-5-yl]-1H-pyridin-2-one     (E4), -   trans-1-Butyl-3-chloro-4-[1-(4-hydroxy-4-methyl-cyclohexyl)-1H-indol-5-yl]-1H-pyridin-2-one     (E5), -   cis-1-Butyl-3-chloro-4-[1-(4-hydroxy-4-methyl-cyclohexyl)-1H-indol-5-yl]-1H-pyridin-2-one     (E6), -   trans-3-Chloro-4-[1-(4-hydroxy-cyclohexyl)-1H-indol-5-yl]-1-(3-methyl-butyl)-1H-pyridin-2-one     (E7), -   trans-3-Chloro-1-cyclopropylmethyl-4-[1-(4-hydroxy-cyclohexyl)-1H-indol-5-yl]-1H-pyridin-2-one     (E8), -   1-Butyl-3-chloro-4-[1-(tetrahydro-pyran-4-yl)-1H-indol-5-yl]-1H-pyridin-2-one     (E9),     and the pharmaceutically acceptable addition salts and solvates     thereof.

In an embodiment of the present invention, preferably said compound of Formula (I) is

-   trans-1-Butyl-3-chloro-4-[1-(4-hydroxy-cyclohexyl)-1H-indol-5-yl]-1H-pyridin-2-one     (E3) or -   trans-1-Butyl-3-chloro-4-[1-(4-hydroxy-4-methyl-cyclohexyl)-1H-indol-5-yl]-1H-pyridin-2-one     (E5).

Whenever the term “substituted” is used in the present invention, it is meant to indicate that one or more hydrogens, preferably from 1 to 3 hydrogens, more preferably 1 hydrogen, on the atom or radical indicated in the expression using “substituted” are replaced with a selection from the indicated group, provided that the normal valency is not exceeded, and that the substitution results in a chemically stable compound, i.e. a compound that is sufficiently robust to survive isolation to a useful degree of purity from a reaction mixture, and formulation into a therapeutic agent. For example, when phenyl is substituted with halo, this means that said phenyl is substituted with one or more substituents selected from halo.

The notation C₁₋₃alkyl as a group or part of a group defines a saturated, straight or branched, hydrocarbon radical having from 1 to 3 carbon atoms such as, for example, methyl, ethyl, 1-propyl and 1-methylethyl.

The notation C₁₋₆alkyl as a group or part of a group defines a saturated, straight or branched, hydrocarbon radical having from 1 to 6 carbon atoms such as, for example, methyl, ethyl, 1-propyl, 1-methylethyl, 1-butyl, 2-methyl-1-propyl, 3-methyl-1-butyl, 1-pentyl, 1-hexyl and the like.

The notation C₃₋₇cycloalkyl defines a saturated, cyclic hydrocarbon radical having from 3 to 7 carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and cycloheptyl.

The notation halo or halogen as a group or part of a group is generic for fluoro, chloro, bromo, iodo.

For therapeutic use, salts of the compounds of formula (I) are those wherein the counterion is pharmaceutically acceptable. However, salts of acids and bases which are non-pharmaceutically acceptable may also find use, for example, in the preparation or purification of a pharmaceutically acceptable compound. All salts, whether pharmaceutically acceptable or not, are included within the ambit of the present invention.

The pharmaceutically acceptable salts are defined to comprise the therapeutically active non-toxic acid addition salt forms that the compounds according to Formula (I) are able to form. Said salts can be obtained by treating the base form of the compounds according to Formula (I) with appropriate acids, for example inorganic acids, for example hydrohalic acid, in particular hydrochloric acid, hydrobromic acid, sulphuric acid, nitric acid and phosphoric acid; organic acids, for example acetic acid, hydroxyacetic acid, propanoic acid, lactic acid, pyruvic acid, oxalic acid, malonic acid, succinic acid, maleic acid, fumaric acid, malic acid, tartaric acid, citric acid, methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, cyclamic acid, salicylic acid, p-aminosalicylic acid and pamoic acid.

Conversely said salt forms can be converted into the free base form by treatment with an appropriate base.

The compounds according to Formula (I) containing acidic protons may also be converted into their therapeutically active non-toxic base salt forms by treatment with appropriate organic and inorganic bases. Appropriate base salt forms comprise, for example, the ammonium salts, the alkaline and earth alkaline metal salts, in particular lithium, sodium, potassium, magnesium and calcium salts, salts with organic bases, e.g. the benzathine, N-methyl-D-glucamine, hybramine salts, and salts with amino acids, for example arginine and lysine.

Conversely, said salt forms can be converted into the free acid forms by treatment with an appropriate acid.

The term solvate comprises the solvent addition forms as well as the salts thereof, which the compounds of formula (I) are able to form. Examples of such solvent addition forms are e.g. hydrates, alcoholates and the like.

The term “stereochemically isomeric forms” as used hereinbefore defines all the possible isomeric forms that the compounds of Formula (I) may possess. Unless otherwise mentioned or indicated, the chemical designation of compounds denotes the mixture of all possible stereochemically isomeric forms, said mixtures containing all diastereomers and enantiomers of the basic molecular structure. The invention also embraces each of the individual isomeric forms of the compounds of Formula (I) and their salts and solvates, substantially free, i.e. associated with less than 10%, preferably less than 5%, in particular less than 2% and most preferably less than 1% of the other isomers. Thus, when a compound of formula (I) is for instance specified as (R), this means that the compound is substantially free of the (S) isomer. Stereogenic centers may have the R- or S-configuration; substituents on bivalent cyclic (partially) saturated radicals may have either the cis- or trans-configuration.

Following CAS nomenclature conventions, when two stereogenic centers of known absolute configuration are present in a compound, an R or S descriptor is assigned (based on Cahn-Ingold-Prelog sequence rule) to the lowest-numbered chiral center, the reference center. The configuration of the second stereogenic center is indicated using relative descriptors [R*,R*] or [R*,S*], where R* is always specified as the reference center and [R*,R*] indicates centers with the same chirality and [R*,S*] indicates centers of unlike chirality. For example, if the lowest-numbered chiral center in the compound has an S configuration and the second center is R, the stereo descriptor would be specified as S—[R*,S*]. If “α” and “β” are used: the position of the highest priority substituent on the asymmetric carbon atom in the ring system having the lowest ring number, is arbitrarily always in the “α” position of the mean plane determined by the ring system. The position of the highest priority substituent on the other asymmetric carbon atom in the ring system (hydrogen atom in compounds according to Formula (I)) relative to the position of the highest priority substituent on the reference atom is denominated “α”, if it is on the same side of the mean plane determined by the ring system, or “β”, if it is on the other side of the mean plane determined by the ring system.

In the framework of this application, an element, in particular when mentioned in relation to a compound according to Formula (I), comprises all isotopes and isotopic mixtures of this element, either naturally occurring or synthetically produced, either with natural abundance or in an isotopically enriched form. Radiolabelled compounds of Formula (I) may comprise a radioactive isotope selected from the group of ³H, ¹¹C, ¹⁸F, ¹²²I, ¹²³I, ¹²⁵I, ¹³¹I, ⁷⁵Br, ⁷⁶Br, ⁷⁷Br and ⁸²Br. Preferably, the radioactive isotope is selected from the group of ³H, ¹¹C and ¹⁸F.

A compound according to the invention therefore inherently comprises a compound with one or more isotopes of one or more elements, and mixtures thereof, including a radioactive compound, also called radiolabelled compound, wherein one or more non-radioactive atoms has been replaced by one of its radioactive isotopes. By the term “radiolabelled compound” is meant any compound according to formula (I), or a pharmaceutically acceptable salt thereof, which contains at least one radioactive atom. For example, a compound can be labelled with positron or with gamma emitting radioactive isotopes. For radioligand-binding techniques, the ³H-atom or the ¹²⁵I-atom is the atom of choice to be replaced. For imaging, the most commonly used positron emitting (PET) radioactive isotopes are ¹¹C, ¹⁸F, ¹⁵O and ¹³N, all of which are accelerator produced and have half-lives of 20, 100, 2 and 10 minutes (min) respectively. Since the half-lives of these radioactive isotopes are so short, it is only feasible to use them at institutions which have an accelerator on site for their production, thus limiting their use. The most widely used of these are ¹⁸F, ^(99m)Tc, ²⁰¹Tl and ¹²³I. The handling of these radioactive isotopes, their production, isolation and incorporation in a molecule are known to the skilled person.

In particular, the radioactive atom is selected from the group of hydrogen, carbon, nitrogen, sulfur, oxygen and halogen. In particular, the radioactive isotope is selected ¹¹C, ¹⁸F, ¹²²I, ¹²³I, ¹²⁵I, from the group of ³H, ¹⁸F, ¹²²I, ¹²³I, ¹²⁵I, ¹³¹I, ⁷⁵Br, ⁷⁶Br, ⁷⁷Br and ⁸²Br.

In an embodiment, radiolabelled compounds of the present invention may be used as positron emission tomography (PET) radioligands for imaging the metabotropic glutamate receptor subtype 2 (mGluR2). Radionuclides typically used in PET are, for example, ¹¹C, ¹⁸F, ¹⁵O, and ¹³N, in particular ¹⁸F.

As used in the specification and the appended claims, the singular forms “a”, “an,” and “the” also include plural referents unless the context clearly dictates otherwise. For example, “a compound” means 1 compound or more than 1 compound.

The terms described above and others used in the specification are well understood to those in the art.

Preparation

The compounds according to the invention can generally be prepared by a succession of steps, each of which is known to the skilled person. In particular, the compounds can be prepared according to the following synthesis methods.

The compounds of Formula (I) may be synthesized in the form of racemic mixtures of enantiomers which can be separated from one another following art-known resolution procedures. The racemic compounds of Formula (I) may be converted into the corresponding diastereomeric salt forms by reaction with a suitable chiral acid. Said diastereomeric salt forms are subsequently separated, for example, by selective or fractional crystallization and the enantiomers are liberated therefrom by alkali. An alternative manner of separating the enantiomeric forms of the compounds of Formula (I) involves liquid chromatography using a chiral stationary phase. Said pure stereochemically isomeric forms may also be derived from the corresponding pure stereochemically isomeric forms of the appropriate starting materials, provided that the reaction occurs stereospecifically.

A. Preparation of the Final Compounds Experimental Procedure 1

The compounds according to Formula (I) can be prepared by reacting an intermediate of Formula (II) with an intermediate of Formula (III) according to reaction scheme 1 wherein Z is a group suitable for Pd mediated coupling with boronic acids or boronic esters such as, for example, a halogen or triflate, and R⁵ and R⁶ may be hydrogen or alkyl, for example C₁₋₆alkyl, or may be taken together to form, for example, the bivalent radical of formula —CH₂CH₂—, —CH₂CH₂CH₂—, or —C(CH₃)₂C(CH₃)₂; and wherein all other variables are defined as in Formula (I). The reaction may be performed in a suitable reaction-inert solvent such as, for example, 1,4-dioxane or a mixture of inert solvents such as, for example, 1,4-dioxane/N,N-dimethylformamide (DMF). The reaction can be performed in the presence of a suitable base such as, for example, aqueous NaHCO₃ or aqueous Na₂CO₃. The reaction may conveniently be carried out in the presence of a Pd-complex catalyst such as, for example, tetrakis(triphenylphosphine)palladium(0). The reaction mixture may be heated for a suitable period of time to allow the completion of the reaction, either under traditional heating or under microwave irradiation.

Experimental Procedure 2

The compounds according to Formula (I) wherein Y is —CH(OH)—, hereby named (I-a), can also be prepared by reacting an intermediate of Formula (IV) under reductive conditions that are known by those skilled in the art. The reaction is illustrated in reaction scheme 2 wherein all substituents are defined as mentioned before. The reaction can be carried out in the presence of, for example, sodium borohydride, in a suitable solvent such as, for example, methanol. The reaction may be performed at a suitable temperature, typically room temperature, for a suitable period of time that allows the completion of the reaction.

Experimental Procedure 3

The compounds according to Formula (I) wherein Y is —C(C₁₋₃alkyl)(OH)—, hereby named (I-b), can be prepared by art known procedures by reacting an intermediate of Formula (IV) with a suitable C₁₋₃alkyl source such as, for example, C₁₋₃alkylmagnesium bromide or C₁₋₃alkyllithium. This reaction is shown in reaction scheme 3 wherein halide is a suitable halogen such as, for example, bromo and all other substituents are defined as mentioned before. The reaction can be carried out in an inert solvent such as, for example, tetrahydrofuran (THF), diethyl ether or dioxane. Typically, the mixture can be stirred for 1 to 48 hours at a temperature between 0-100° C.

B. Preparation of the Intermediates Experimental Procedure 4

Intermediates of Formula (II) wherein Z is triflate, hereby named (II-a), can be prepared by reacting an intermediate of Formula (V) with triflic anhydride (also called trifluoromethanesulfonic anhydride) according to reaction scheme 4 wherein all variables are defined as in Formula (I). The reaction can be performed in a suitable reaction-inert solvent such as, for example, dichloromethane (DCM). The reaction may be performed in the presence of a base such as, for example, pyridine. The reaction may conveniently be carried out at a low temperature such as, for example, −78° C.

Experimental Procedure 5

Intermediates of Formula (V) wherein R² is restricted to R^(2a) (halo), hereby called Formula (V-a), can be prepared by reacting an intermediate of Formula (VI) with a N-halosuccinimide reagent, such as N-chlorosuccinimide, N-bromosuccinimide or N-iodosuccinimide, according to reaction scheme 5 wherein R^(2a) is defined as halo and wherein all other variables are defined as in Formula (I). This reaction can be performed in a suitable reaction-inert and aprotic solvent such as, for example, DCM or 1,2-dichloroethane (DCE). The reaction mixture can be stirred at a suitable temperature, typically at room temperature, for the required time to achieve completion of the reaction.

Experimental Procedure 6

Intermediates of Formula (V) wherein R² is restricted to R^(2b) (trifluoromethyl, C₁₋₃alkyl or cyclopropyl), hereby named (V-b), can be prepared by hydrogenation of intermediates of Formula (VII) according to reaction scheme 6 wherein R^(2b) is trifluoromethyl, C₁₋₃alkyl or cyclopropyl and wherein all other variables are defined as in Formula (I). The reaction may be performed in a suitable reaction-inert solvent such as, for example, ethanol. The reaction can be performed in the presence of a catalyst such as, for example, 10% palladium on activated carbon, for a period of time that ensures the completion of the reaction. The reaction typically can be carried out at room temperature and 1 atmosphere of hydrogen for 2 hours.

Experimental Procedure 7

Intermediates of Formula (VI) can be prepared by hydrogenolysis of intermediates of Formula (VIII) according to reaction scheme 7 wherein all variables are defined as in Formula (I). This reaction can be performed in a suitable reaction-inert solvent such as, for example, ethanol. The reaction may be carried out in the presence of a catalyst such as, for example, 10% palladium on activated carbon, for a period of time that ensures the completion of the reaction. The reaction typically can be performed at room temperature and 1 atmosphere of hydrogen for 2 hours.

Experimental Procedure 8

Intermediates of Formula (VIII) can be prepared by art known procedures by reacting commercially available 4-benzyloxy-1H-pyridin-2-one with a commercially available alkylating agent of Formula (IX) according to reaction scheme 8 in which Q is a suitable leaving group such as, for example, a halogen, and wherein R¹ is defined as in Formula (I). The reaction typically is performed using a base such as, for example, K₂CO₃, and optionally in the presence of a iodine salt such as, for example, KI. The reaction can be carried out in an inert solvent such as, for example, CH₃CN or DMF. The reaction may conveniently be carried out a moderately high temperature such as, for example, 80-120° C., for a suitable period of time that allows the completion of the reaction, for example 16 hours.

Experimental Procedure 9

Intermediates of Formula (VII) wherein R^(2b) is restricted to R^(2c) (CF₃), hereby named (VII-b), can be prepared by reacting an intermediate of Formula (VII-a) wherein halo is restricted to iodine, hereby named (VII-a1), with commercially available methyl 2,2-difluoro-2-(fluorosulfonyl)acetate according to reaction scheme 9 wherein R^(2c) is CF₃ and wherein R¹ is defined as in Formula (I). The reaction can be performed in a suitable reaction-inert solvent such as, for example, DMF. The reaction may be carried out in the presence of a suitable copper salt such as, for example, copper(I) iodide. Heating can be applied for a suitable period of time to allow the completion of the reaction, for example, at 100° C. for 5 hours.

Experimental Procedure 10

Intermediates of Formula (VII) wherein R² is restricted to R^(2c) (C₁₋₃alkyl or cyclopropyl), hereby named (VII-c), can be prepared by reacting an intermediate of Formula (VII-a) with a C₁₋₃alkyl- or cyclopropyl-boronic acid derivative such as, for example, cyclopropylboronic acid or methylboronic acid according to reaction scheme 10 wherein R^(2c) is defined as C₁₋₃alkyl or cyclopropyl and wherein all other variables are defined as in Formula (I). The reaction may be performed in a suitable reaction-inert solvent such as, for example, 1,4-dioxane. The reaction can be carried out in the presence of a suitable palladium catalyst-complex such as, for example, a [1,1′-bis(diphenylphosphino)-ferrocene]-dichloropalladium(II)-DCM complex. The reaction can be performed in the presence of a suitable base such as, for example, NaHCO₃. Heating can be applied for a suitable period of time to allow the completion of the reaction, for example at 175° C. for 20 minutes under microwave irradiation.

Experimental Procedure 11

Intermediates of Formula (VII-a) can be prepared by reacting an intermediate of Formula (VIII) with a commercially available N-halosuccinimide such as, for example, N-chloro- (NCS), N-bromo- (NBS) or N-iodosuccinimide (NIS) as is illustrated in reaction scheme 11 wherein all variables are defined as mentioned before. The reaction can be performed in a suitable reaction-inert solvent such as, for example, DMF, DCM or acetic acid. The reaction may typically be carried out at room temperature for 1 to 24 hours.

Experimental Procedure 12

Intermediates of Formula (III) can be prepared by art known procedures by reacting an intermediate of Formula (X) with a suitable boron source such as, for example, bis(pinacolato)diboron as is shown in reaction scheme 12 wherein all variables are defined as in Formula (I). The reaction can be performed in the presence of a palladium catalyst such as, for example, 1,1′-bis(diphenylphosphino)ferrocenepalladium(II)dichloride in an inert solvent such as, for example, DCM. The reaction may be carried out in the presence of a suitable salt such as, for example, potassium acetate at a moderately high temperature such as, for example, 110° C. during, for example, 16 hours.

Additionally, intermediates of Formula (III) can be prepared by art known procedures of metal-halogen exchange and subsequent reaction with an appropriate boron source from intermediates of Formula (X). This type of reaction can be carried out by using, for example, an intermediate of Formula (X) and an organolithium compound such as, for example, n-butyllithium. The reaction can be performed at a moderately low temperature such as, for example, −40° C. in an inert solvent such as, for example, THF. This reaction is followed by subsequent reaction with an appropriate boron source such as, for example, trimethoxyborane.

In reaction scheme (12), R⁵ and R⁶ are defined as mentioned before, halo is a suitable halogen such as, for example, bromo and all other variables are defined as in Formula (I).

Intermediates of Formula (X) wherein Y is —O—, can be prepared according to experimental procedure 17 and experimental procedure 18.

Experimental Procedure 13

Intermediates of Formula (X) wherein Y is —C(C₁₋₃alkyl)(OH)—, hereby named (X-a), can be prepared by art known procedures by reacting an intermediate of Formula (XI) with a suitable C₁₋₃alkyl source such as, for example, C₁₋₃alkylmagnesium bromide or C₁₋₃alkyllithium. This reaction is shown in reaction scheme 13 wherein halo is a suitable halogen such as, for example, bromo and all other substituents are defined as mentioned before. The reaction can be carried out in an inert solvent such as, for example, THF, diethyl ether or dioxane. Typically, the mixture can be stirred for 1 to 48 hours at a temperature between 0-100° C.

Experimental Procedure 14

Intermediates of Formula (X) wherein Y is —CH(OH)—, hereby named (X-b), can be prepared by reacting an intermediate of Formula (XI) under reductive conditions that are known by those skilled in the art. The reaction is illustrated in reaction scheme 14 wherein all substituents are defined as mentioned before. The reaction can be carried out in the presence of, for example, sodium borohydride in a suitable solvent such as, for example, methanol. The reaction may be performed at a suitable temperature, typically room temperature, for a suitable period of time that allows the completion of the reaction.

Experimental Procedure 15

Intermediates of Formula (IV) can be prepared by reacting an intermediate of Formula (III) wherein Y is restricted to —CH(OH)—, hereby named (III-a), with an intermediate of Formula (II), according to reaction scheme 15 wherein Z is a group suitable for Pd mediated coupling with boronic acids or boronic esters such as, for example, a halogen or triflate, R⁵ and R⁶ may be hydrogen or alkyl, or may be taken together to form for example the bivalent radical of formula —CH₂CH₂—, —CH₂CH₂CH₂—, or —C(CH₃)₂C(CH₃)₂— and all other variables are defined as mentioned before. The reaction can be performed in a suitable reaction-inert solvent, such as, for example, 1,4-dioxane or in a mixture of inert solvents such as, for example, 1,4-dioxane/DMF. The reaction may be carried out in the presence of a suitable base such as, for example, aqueous NaHCO₃ or aqueous Na₂CO₃. The reaction can be performed using a Pd-complex catalyst such as, for example, tetrakis(triphenylphosphine)palladium(0). Usually, the reaction mixture is heated for a suitable period of time to allow the completion of the reaction either under traditional heating or under microwave irradiation.

Experimental Procedure 16

Intermediates of Formula (XI) can be prepared by subjecting an intermediate of Formula (XII) to acidic conditions that are known by those skilled in the art. This reaction is illustrated in reaction scheme 16 wherein all variables are defined as mentioned before. The reaction can be performed in the presence of an acid such as, for example, p-toluenesulfonic acid. The reaction can be performed in a suitable reaction solvent such as, for example, acetone. The reaction may conveniently be carried out under microwave irradiation at a suitable temperature, typically at 100° C., for a suitable period of time that allows the completion of the reaction.

Intermediates of Formula (XII) can be prepared according to experimental procedure 17 and experimental procedure 18.

Experimental Procedure 17

Intermediates of Formula (XIII) can be prepared by reacting the commercially available intermediate of Formula (XV) with a tosylate derivative of Formula (XIV) according to reaction scheme 17 wherein W is —O— or

according to reaction scheme 17 wherein halo is a suitable halogen such as, for example, bromo, Ts means tosylate and all other variables are defined as in Formula (I). The intermediate of Formula (XIV) wherein W=—O— and n=1 is commercially available (CAS [13694-84-3]); W=—O— and n=2 (CAS [97986-34-0]) can be prepared according to the synthetic procedure described in WO 2007148648 A1;

n=2 (CAS [23511-05-9]) can be prepared according to the synthetic procedure described in J. Chem. Soc., Perkin Trans. 1, 2002, 2251-2255; and

n=1 can be prepared in analogy to the synthetic procedure described in J. Chem. Soc., Perkin Trans. 1, 2002, 2251-2255 but starting from 1,4-dioxaspiro[4.4]nonan-7-ol. The reaction according to reaction scheme 17 can be carried out under alkylation conditions that are known by those skilled in the art such as, for example, in the presence of base such as, for example, potassium hydroxide in a suitable reaction solvent such as, for example, dimethylsulphoxide. The reaction may be performed at a suitable temperature, typically at 60° C., for a suitable period of time that allows the completion of the reaction.

Experimental Procedure 18

Intermediates of Formula (XVI), can be prepared by reacting the commercially available 1,2-dibromoethane with an aminophenol derivative of Formula (XVII) under alkylation conditions as is illustrated in reaction scheme 18, wherein all variables are defined as in Formula (I) and experimental procedure 17. Such alkylation conditions are known by those skilled in the art, such as for example, in the presence of a base such as for example K₂CO₃ in a suitable reaction solvent such as, for example, DMF. The reaction may be carried out under microwave irradiation at a suitable temperature, typically 180° C., for a suitable period of time that allows the completion of the reaction.

Experimental Procedure 19

Intermediates of Formula (XVII) can be prepared by reacting an intermediate of Formula (XVIII) with a commercially available N-halosuccinimide such as N-chloro-(NCS), N-bromo- (NBS) or N-iodosuccinimide (NIS) according to reaction scheme 19 wherein all variables are defined as in Formula (I) and experimental procedure 17. This reaction can be performed in a suitable reaction-inert solvent such as, for example, DMF, DCM or acetic acid. The reaction typically can be carried out at room temperature for 1 to 24 hours.

Experimental Procedure 20

Intermediates of Formula (XVIII) can be prepared by reacting an intermediate of Formula (XX) with a cyclic ketone derivative of Formula (XIX) under reductive amination conditions that are known by those skilled in the art. This is illustrated in reaction scheme 20 wherein all variables are defined as in mentioned hereabove. The reaction may be performed, for example, in the presence of triacetoxy borohydride in a suitable reaction-inert solvent such as, for example, DCE, at a suitable temperature, typically at room temperature, for a suitable period of time that allows the completion of the reaction.

Intermediates of Formula (XIX) are commercially available or can be prepared by those skilled in the art.

The intermediate of Formula (XX) wherein R³ is Cl, can be prepared according to the synthetic procedure described in Journal of the Chemical Society (1963), (November), 5571-2. The intermediate of Formula (XX) wherein R³ is H is commercially available.

Pharmacology

The compounds provided in this invention are positive allosteric modulators of metabotropic glutamate receptors, in particular they are positive allosteric modulators of mGluR2. The compounds of the present invention do not appear to bind to the glutamate recognition site, the orthosteric ligand site, but instead to an allosteric site within the seven transmembrane region of the receptor. In the presence of glutamate or an agonist of mGluR2, the compounds of this invention increase the mGluR2 response. The compounds provided in this invention are expected to have their effect at mGluR2 by virtue of their ability to increase the response of such receptors to glutamate or mGluR2 agonists, enhancing the response of the receptor. Hence, the present invention relates to a compound according to the present invention for use as a medicament. The present invention also relates to a compound according to the invention or a pharmaceutical composition according to the invention for use in the treatment or prevention, in particular treatment, of a disease or a condition in a mammal, including a human, the treatment or prevention of which is affected or facilitated by the neuromodulatory effect of allosteric modulators of mGluR2, in particular positive allosteric modulators thereof. The present invention also relates to the use of a compound according to the invention or a pharmaceutical composition according to the invention for the manufacture of a medicament for treating or preventing, in particular treating, a condition in a mammal, including a human, the treatment or prevention of which is affected or facilitated by the neuromodulatory effect of allosteric modulators of mGluR2, in particular positive allosteric modulators thereof. The present invention also relates to a compound according to the present invention or a pharmaceutical composition according to the invention for use in the manufacture of a medicament for treating or preventing, in particular treating, a condition in a mammal, including a human, the treatment or prevention of which is affected or facilitated by the neuromodulatory effect of allosteric modulators of mGluR2, in particular positive allosteric modulators thereof. The present invention also relates to a compound according to the present invention or a pharmaceutical composition according to the invention for treating or preventing, in particular treating, a condition in a mammal, including a human, the treatment or prevention of which is affected or facilitated by the neuromodulatory effect of allosteric modulators of mGluR2, in particular positive allosteric modulators thereof.

Also, the present invention relates to the use of a compound according to the invention or a pharmaceutical composition according to the invention for the manufacture of a medicament for treating, preventing, ameliorating, controlling or reducing the risk of various neurological and psychiatric disorders associated with glutamate dysfunction in a mammal, including a human, the treatment or prevention of which is affected or facilitated by the neuromodulatory effect of positive allosteric modulators of mGluR2.

Where the invention is said to relate to the use of a compound or composition according to the invention for the manufacture of a medicament for e.g. the treatment of a mammal, it is understood that such use is to be interpreted in certain jurisdictions as a method of e.g. treatment of a mammal, comprising administering to a mammal in need of such e.g. treatment, an effective amount of a compound or composition according to the invention.

In particular, the neurological and psychiatric disorders associated with glutamate dysfunction, include one or more of the following conditions or diseases: acute neurological and psychiatric disorders such as, for example, cerebral deficits subsequent to cardiac bypass surgery and grafting, stroke, cerebral ischemia, spinal cord trauma, head trauma, perinatal hypoxia, cardiac arrest, hypoglycemic neuronal damage, dementia (including AIDS-induced dementia), Alzheimer's disease, Huntington's Chorea, amyotrophic lateral sclerosis, ocular damage, retinopathy, cognitive disorders, idiopathic and drug-induced Parkinson's disease, muscular spasms and disorders associated with muscular spasticity including tremors, epilepsy, convulsions, migraine (including migraine headache), urinary incontinence, substance tolerance, substance withdrawal (including substances such as, for example, opiates, nicotine, tobacco products, alcohol, benzodiazepines, cocaine, sedatives, hypnotics, etc.), psychosis, schizophrenia, anxiety (including generalized anxiety disorder, panic disorder, and obsessive compulsive disorder), mood disorders (including depression, mania, bipolar disorders), trigeminal neuralgia, hearing loss, tinnitus, macular degeneration of the eye, emesis, brain edema, pain (including acute and chronic states, severe pain, intractable pain, neuropathic pain, and post-traumatic pain), tardive dyskinesia, sleep disorders (including narcolepsy), attention deficit/hyperactivity disorder, and conduct disorder.

In particular, the condition or disease is a central nervous system disorder selected from the group of anxiety disorders, psychotic disorders, personality disorders, substance-related disorders, eating disorders, mood disorders, migraine, epilepsy or convulsive disorders, childhood disorders, cognitive disorders, neurodegeneration, neurotoxicity and ischemia.

Preferably, the central nervous system disorder is an anxiety disorder, selected from the group of agoraphobia, generalized anxiety disorder (GAD), obsessive-compulsive disorder (OCD), panic disorder, posttraumatic stress disorder (PTSD), social phobia and other phobias.

Preferably, the central nervous system disorder is a psychotic disorder selected from the group of schizophrenia, delusional disorder, schizoaffective disorder, schizophreniform disorder and substance-induced psychotic disorder

Preferably, the central nervous system disorder is a personality disorder selected from the group of obsessive-compulsive personality disorder, schizoid personality disorder, and schizotypal personality disorder.

Preferably, the central nervous system disorder is a substance-related disorder selected from the group of alcohol abuse, alcohol dependence, alcohol withdrawal, alcohol withdrawal delirium, alcohol-induced psychotic disorder, amphetamine dependence, amphetamine withdrawal, cocaine dependence, cocaine withdrawal, nicotine dependence, nicotine withdrawal, opioid dependence and opioid withdrawal.

Preferably, the central nervous system disorder is an eating disorder selected from the group of anorexia nervosa and bulimia nervosa.

Preferably, the central nervous system disorder is a mood disorder selected from the group of bipolar disorders (I & II), cyclothymic disorder, depression, dysthymic disorder, major depressive disorder and substance-induced mood disorder.

Preferably, the central nervous system disorder is migraine.

Preferably, the central nervous system disorder is epilepsy or a convulsive disorder selected from the group of generalized nonconvulsive epilepsy, generalized convulsive epilepsy, petit mal status epilepticus, grand mal status epilepticus, partial epilepsy with or without impairment of consciousness, infantile spasms, epilepsy partialis continua, and other forms of epilepsy.

Preferably, the central nervous system disorder is attention-deficit/hyperactivity disorder.

Preferably, the central nervous system disorder is a cognitive disorder selected from the group of delirium, substance-induced persisting delirium, dementia, dementia due to HIV disease, dementia due to Huntington's disease, dementia due to Parkinson's disease, dementia of the Alzheimer's type, substance-induced persisting dementia and mild cognitive impairment.

Of the disorders mentioned above, the treatment of anxiety, schizophrenia, migraine, depression, and epilepsy are of particular importance.

At present, the fourth edition of the Diagnostic & Statistical Manual of Mental Disorders (DSM-IV) of the American Psychiatric Association provides a diagnostic tool for the identification of the disorders described herein. The person skilled in the art will recognize that alternative nomenclatures, nosologies, and classification systems for neurological and psychiatric disorders described herein exist, and that these evolve with medical and scientific progresses.

Because such positive allosteric modulators of mGluR2, including compounds of Formula (I), enhance the response of mGluR2 to glutamate, it is an advantage that the present methods utilize endogenous glutamate.

Because positive allosteric modulators of mGluR2, including compounds of Formula (I), enhance the response of mGluR2 to agonists, it is understood that the present invention extends to the treatment of neurological and psychiatric disorders associated with glutamate dysfunction by administering an effective amount of a positive allosteric modulator of mGluR2, including compounds of Formula (I), in combination with an mGluR2 agonist.

The compounds of the present invention may be utilized in combination with one or more other drugs in the treatment, prevention, control, amelioration, or reduction of risk of diseases or conditions for which compounds of Formula (I) or the other drugs may have utility, where the combination of the drugs together are safer or more effective than either drug alone.

Pharmaceutical Compositions

The invention also relates to a pharmaceutical composition comprising a pharmaceutically acceptable carrier or diluent and, as active ingredient, a therapeutically effective amount of a compound according to the invention, in particular a compound according to Formula (I), a pharmaceutically acceptable salt thereof, a solvate thereof or a stereochemically isomeric form thereof.

The invention also relates to a pharmaceutical composition comprising a therapeutically effective amount of a compound according to Formula (I) and a pharmaceutically acceptable carrier or excipient.

The compounds according to the invention, in particular the compounds according to Formula (I), the pharmaceutically acceptable salts thereof, the solvates and the stereochemically isomeric forms thereof, or any subgroup or combination thereof may be formulated into various pharmaceutical forms for administration purposes. As appropriate compositions there may be cited all compositions usually employed for systemically administering drugs.

To prepare the pharmaceutical compositions of this invention, an effective amount of the particular compound, optionally in salt form, as the active ingredient is combined in intimate admixture with a pharmaceutically acceptable carrier or diluent, which carrier or diluent may take a wide variety of forms depending on the form of preparation desired for administration. These pharmaceutical compositions are desirable in unitary dosage form suitable, in particular, for administration orally, rectally, percutaneously, by parenteral injection or by inhalation. For example, in preparing the compositions in oral dosage form, any of the usual pharmaceutical media may be employed such as, for example, water, glycols, oils, alcohols and the like in the case of oral liquid preparations such as, for example, suspensions, syrups, elixirs, emulsions and solutions; or solid carriers such as, for example, starches, sugars, kaolin, diluents, lubricants, binders, disintegrating agents and the like in the case of powders, pills, capsules and tablets. Because of the ease in administration, oral administration is preferred, and tablets and capsules represent the most advantageous oral dosage unit forms in which case solid pharmaceutical carriers are obviously employed. For parenteral compositions, the carrier will usually comprise sterile water, at least in large part, though other ingredients, for example, to aid solubility, may be included. Injectable solutions, for example, may be prepared in which the carrier comprises saline solution, glucose solution or a mixture of saline and glucose solution. Injectable suspensions may also be prepared in which case appropriate liquid carriers, suspending agents and the like may be employed. Also included are solid form preparations that are intended to be converted, shortly before use, to liquid form preparations. In the compositions suitable for percutaneous administration, the carrier optionally comprises a penetration enhancing agent and/or a suitable wetting agent, optionally combined with suitable additives of any nature in minor proportions, which additives do not introduce a significant deleterious effect on the skin. Said additives may facilitate the administration to the skin and/or may be helpful for preparing the desired compositions. These compositions may be administered in various ways, e.g., as a transdermal patch, as a spot-on, as an ointment.

It is especially advantageous to formulate the aforementioned pharmaceutical compositions in unit dosage form for ease of administration and uniformity of dosage. Unit dosage form as used herein refers to physically discrete units suitable as unitary dosages, each unit containing a predetermined quantity of active ingredient calculated to produce the desired therapeutic effect in association with the required pharmaceutical carrier. Examples of such unit dosage forms are tablets (including scored or coated tablets), capsules, pills, powder packets, wafers, suppositories, injectable solutions or suspensions and the like, and segregated multiples thereof.

The exact dosage and frequency of administration depends on the particular compound of formula (I) used, the particular condition being treated, the severity of the condition being treated, the age, weight, sex, extent of disorder and general physical condition of the particular patient as well as other medication the individual may be taking, as is well known to those skilled in the art. Furthermore, it is evident that said effective daily amount may be lowered or increased depending on the response of the treated subject and/or depending on the evaluation of the physician prescribing the compounds of the instant invention.

Depending on the mode of administration, the pharmaceutical composition will comprise from 0.05 to 99% by weight, preferably from 0.1 to 70% by weight, more preferably from 0.1 to 50% by weight of the active ingredient, and, from 1 to 99.95% by weight, preferably from 30 to 99.9% by weight, more preferably from 50 to 99.9% by weight of a pharmaceutically acceptable carrier, all percentages being based on the total weight of the composition.

As already mentioned, the invention also relates to a pharmaceutical composition comprising the compounds according to the invention and one or more other drugs in the treatment, prevention, control, amelioration, or reduction of risk of diseases or conditions for which compounds of Formula (I) or the other drugs may have utility as well as to the use of such a composition for the manufacture of a medicament. The present invention also relates to a combination of a compound according to the present invention and a mGluR2 orthosteric agonist. The present invention also relates to such a combination for use as a medicament. The present invention also relates to a product comprising (a) a compound according to the present invention, a pharmaceutically acceptable salt thereof or a solvate thereof, and (b) a mGluR2 orthosteric agonist, as a combined preparation for simultaneous, separate or sequential use in the treatment or prevention of a condition in a mammal, including a human, the treatment or prevention of which is affected or facilitated by the neuromodulatory effect of mGluR2 allosteric modulators, in particular positive mGluR2 allosteric modulators. The present invention also relates to a compound according to the invention in combination with an orthosteric agonist of mGluR2 for use in the treatment or prevention of the above mentioned diseases or conditions. The different drugs of such a combination or product may be combined in a single preparation together with pharmaceutically acceptable carriers or diluents, or they may each be present in a separate preparation together with pharmaceutically acceptable carriers or diluents.

The present invention also relates to a compound according to the invention and an orthosteric agonist of mGluR2 as a combined preparation for simultaneous, separate or sequential use in the treatment or prevention of the above mentioned diseases or conditions.

The following examples are intended to illustrate but not to limit the scope of the present invention.

Chemistry

Several methods for preparing the compounds of this invention are illustrated in the following Examples. Unless otherwise noted, all starting materials were obtained from commercial suppliers and used without further purification.

Hereinafter, “THF” means tetrahydrofuran; “DMF” means N,N-dimethylformamide; “EtOAc” means ethyl acetate; “DCM” means dichloromethane; “DME” means 1,2-dimethoxyethane; “DCE” means 1,2-dichloroethane; “DIPE” means diisopropylether; “DMSO” means dimethylsulfoxide; “DBU” means 1,8-diaza-7-bicyclo[5.4.0]undecene, “MeOH” means methanol, ““h.” means hour(s), “s.” means second(s), “min.” means minute(s), “r.t.” means room temperature, “M.P.” means melting point, “r.m.” means reaction mixture;

Microwave assisted reactions were performed in a single-mode reactor: Initiator™ Sixty EXP microwave reactor (Biotage AB), or in a multimode reactor: MicroSYNTH Labstation (Milestone, Inc.).

¹H NMR spectra were recorded on a Bruker DPX-400 and on a Bruker AV-500 spectrometer with standard pulse sequences, operating at 400 MHz and 500 MHz respectively, using CDCL₃ and C₆D₆ as solvents. Chemical shifts (δ) are reported in parts per million (ppm) downfield from tetramethylsilane (TMS), which was used as internal standard.

Description 1 4-Benzyloxy-1-butyl-1H-pyridin-2-one (D1)

1-Bromobutane (3.75 g, 27.33 mmol) and potassium carbonate (10.3 g, 74.52 mmol) were added to a solution of 4-benzyloxy-1H-pyridin-2-one (5.0 g, 24.84 mmol) in CH₃CN (200 ml). The mixture was heated at reflux temperature for 16 h. The r.m. was then filtered through diatomaceous earth and concentrated in vacuo. The crude residue was then triturated with diethyl ether to yield pure D1 (6.26 g, 98%) as a white solid.

Description 2 1-Butyl-4-hydroxy-1H-pyridin-2-one (D2)

A mixture of intermediate D1 (2.01 g, 7.83 mmol) and a catalytic amount of 10% palladium on activated carbon in ethanol (300 ml) was stirred under a H₂ atmosphere for 2 h. The mixture was filtered through diatomaceous earth and the solvent was evaporated in vacuo to yield intermediate D2 (1.3 g, 100%). The crude was used as such in the next reaction step without further purification.

Description 3 1-Butyl-3-chloro-4-hydroxy-1H-pyridin-2-one (D3)

N-chlorosuccinimide (1.6 g, 11.96 mmol) was added to a solution of intermediate D2 (2.0 g, 11.96 mmol) in DMF (30 ml). The mixture was stirred overnight at r.t. and was then concentrated in vacuo. The crude product was purified by column chromatography (silica gel; 0-5% MeOH/DCM as eluent) to yield intermediate D3 (2.0 g, 83%).

Description 4 Trifluoro-methanesulfonic acid 1-butyl-3-chloro-2-oxo-1,2-dihydropyridin-4-yl ester (D4)

Pyridine (1.60 ml, 19.8 mmol) was added to a cooled solution (−78° C.) of intermediate D3 (2.0 g, 9.92 mmol) in DCM (80 ml). The resulting solution was stirred for 10 min. after which trifluoromethanesulfonic anhydride (1.90 ml, 10.9 mmol) was added. The resulting solution was stirred at −78° C. for 3 h. Subsequently, the mixture was warmed to r.t. and was then quenched by the addition of aqueous saturated ammonium chloride. This mixture was diluted with H₂O and extracted with DCM. The separated organic layer was dried (Na₂SO₄), filtered and the solvent was evaporated in vacuo. Yield: 3.31 g of intermediate D4 (100%) as a crude that was used in the next reaction step without further purification.

Description 5 Trifluoro-methanesulfonic acid 3-chloro-1-3-methyl-butyl)-2-oxo-1,2-dihydro-pyridin-4-yl ester (D5)

Intermediate D5 was prepared following the same procedure implemented for the synthesis of D4, but 1-isopentyl-4-hydroxy-1H-pyridin-2-one was used as the starting material. 1-Isopentyl-4-hydroxy-1H-pyridin-2-one was prepared by the same method used for the synthesis of intermediate D2, by reaction of 4-benzyloxy-1H-pyridin-2-one with isopentylbromide.

Description 6 Trifluoro-methanesulfonic acid 3-chloro-1-(3-methyl-butyl)-2-oxo-1,2-dihydro-pyridin-4-yl ester (D6)

Intermediate D6 was prepared following the same procedure implemented for the synthesis of D4, using as starting material 1-cyclopropylmethyl-4-hydroxy-1H-pyridin-2-one which was prepared by the same method used for the synthesis of intermediate D2, by reaction of 4-benzyloxy-1H-pyridin-2-one with cyclopropylmethyl-bromide.

Description 7 2-(Tetrahydro-pyran-4-ylamino)-phenol (D7)

A mixture of 2-aminophenol (1 g, 9.164 mmol), tetrahydropyran-4-one (1.099 ml, 11.913 mmol), and sodium triacetoxy-borohydride (0.71 g, 3.42 mmol) in DCE (50 ml) was stirred at r.t. for 16 h. The crude was filtered over diatomaceous earth, washed with DCM and the filtrate was evaporated in vacuo to yield D7 (0.69 g) that was used as such in the next reaction step without further purification.

Description 8 2-(1,4-Dioxa-spiro[4.5]dec-8-ylamino)-phenol (D8)

A mixture of 2-aminophenol (2 g, 18.327 mmol), 1,4-cyclohexanedione monoethyleneketal (3.721 g, 23.825 mmol), and sodium triacetoxy-borohydride (5.826 g, 27.491 mmol) in DCE (20 ml) and acetic acid (0.2 ml) was stirred at r.t. for 3 h. The r.m. was diluted with DCM and washed with NaHCO₃ aqueous saturated solution, dried (Na₂SO₄) and the solvent was evaporated in vacuo. The solid residue thus obtained was triturated with diisopropyl ether to yield D8 (3.78 g) as a white solid.

Description 9 5-Bromo-2-(tetrahydro-pyran-4-ylamino)-phenol (D9)

A solution of intermediate D7 (0.66 g, 3.415 mmol) and N-bromosuccinimide (0.669 g, 3.757 mmol) in DMF (10 ml) was stirred at r.t. for 1 h. Subsequently, the r.m. was washed with an aqueous saturated NaHCO₃ solution. The organic layer was separated, dried (Na₂SO₄), filtered and the solvent evaporated in vacuo. The crude product was purified by column chromatography (silica gel; DCM/EtOAc 8:2 as eluent). The desired fractions were collected and evaporated in vacuo to yield D9 (0.433 g, 46.6%) as a reddish solid.

Description 10 5-Bromo-2-(1,4-dioxa-spiro[4.5]dec-8-ylamino)-phenol (D10)

A solution of intermediate D8 (1 g, 4.011 mmol) and N-bromosuccinimide (0.785 g, 4.412 mmol) in DMF (15 ml) was stirred at r.t. for 1 h. Subsequently, the r.m. was washed with an aqueous saturated NaHCO₃ solution. The organic layer was separated, dried (Na₂SO₄), filtered and the solvent was evaporated in vacuo. The crude product was purified by column chromatography (silica gel; DCM/EtOAc 8:2 as eluent). The desired fractions were collected and evaporated in vacuo to yield D10 (0.433 g, 32.89%) as a reddish solid.

Description 11 7-Bromo-4-(tetrahydro-pyran-4-yl)-3,4-dihydro-2H-benzo[1,4]oxazine (D11)

A mixture of intermediate D9 (0.433 g, 1.591 mmol), 1,2-dibromoethane (0.411 ml, 4.773 mmol and potassium carbonate (1.099 g, 7.955 mmol) in DMF (10 ml) was heated at 180° C. for 15 min. under microwave irradiation. After cooling to r.t. the r.m. was filtered through diatomaceous earth. The filtrate was evaporated in vacuo. The crude residue was purified by column chromatography (silica gel; DCM as eluent). The desired fractions were collected and evaporated in vacuo to yield a colorless oil that crystallized to yield D11 (0.267 g, 56%) as a white solid.

M.P.: 66.2° C.

Description 12 7-Bromo-4-(1,4-dioxa-spiro[4.5]dec-8-yl)-3,4-dihydro-2H-benzol-[1,4]oxazine (D12)

A mixture of intermediate D10 (0.433 g, 1.319 mmol), 1,2-dibromoethane (0.341 ml, 3.958 mmol and potassium carbonate (0.912 g, 6.596 mmol) in DMF (10 ml) was heated at 180° C. for 15 min. under microwave irradiation. After cooling to r.t. the r.m. was filtered through diatomaceous earth. The filtrate was evaporated in vacuo. The crude residue was purified by column chromatography (silica gel; DCM as eluent). The desired fractions were collected and evaporated in vacuo to yield a colorless oil that crystallized to yield D12 (0.271 g, 58%).

Description 13 4(7-Bromo-2,3-dihydro-benzo[1,4]oxazin-4-yl)-cyclohexanone (D13)

A mixture of intermediate D12 (0.250 g, 0.706 mmol), p-toluenesulfonic acid (13.424 mg, 0.0706 mmol) in H₂O (5 ml) and acetone (2.5 ml) was heated at 100° C. for 15 min. under microwave irradiation. After cooling to r.t. the r.m. was diluted with DCM and washed with a saturated aqueous NaHCO₃ solution, dried (Na₂SO₄) and evaporated in vacuo. The r.m. was purified by column chromatography (silica gel; DCM as eluent). The desired fractions were collected and evaporated in vacuo to yield D13 (0.172 g, 78%) as a white solid.

M.P.: 101.8° C.

Description 14 trans-4-(7-Bromo-2,3-dihydro-benzo[1,4]oxazin-4-yl)-cyclohexanol (D14)

A mixture of intermediate D13 (0.170 g, 0.548 mmol) and sodium borohydride (62.198 mg, 1.644 mmol) in MeOH (10 ml) was stirred at r.t. for 2 h. Then, the resulting mixture was quenched with an aqueous saturated ammonium chloride solution and extracted with DCM. The separated organic layer was collected, dried (Na₂SO₄), filtered and evaporated in vacuo. The residue thus obtained was purified by circular chromatography (silica gel; DCM as eluent). The desired fractions were collected and evaporated in vacuo to yield D14 (0.150 g, 88%) as a white solid (trans).

Description 15 trans-4-[7-(4,4,5,5-Tetramethyl-[1,3,2]dioxaborolan-2-yl)-2,3-dihydro-benzo[1,4]oxazin-4-yl]-cyclohexanol (D15)

Bis(pinacolato)diboron (0.171 g, 0.673 mmol) and potassium acetate (0.141 g, 1.441 mmol) were added to a solution of intermediate D14 (0.150 g, 0.48 mmol) in dioxane (12 ml). The mixture was degassed and then [1,1′-bis(diphenylphosphino)-ferrocene]-dichloropalladium(II)-complex with DCM (1:1) (0.021 g, 0.0288 mmol) was added. The r.m. was heated overnight at 95° C. in a sealed tube. After cooling to r.t., the r.m. was filtered through diatomaceous earth. The filtrate was evaporated in vacuo. The crude residue was purified by column chromatography (silica gel; DCM/EtOAc gradient from 100:0 to 90:10 as eluent). The desired fractions were collected and evaporated in vacuo to afford a colourless oily residue that crystallized to yield D15 (0.123 g, 71%) as a white solid (trans).

Description 16 4-(Tetrahydro-pyran-4-yl)-7-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-3,4-dihydro-2H-benzo[1,4]oxazine (D16)

Bis(pinacolato)diboron (315.956 mg, 1.244 mmol) and potassium acetate (261.659 mg, 2.666 mmol) were added to a solution of intermediate D11 (265 mg, 0.889 mmol) in dioxane (12 ml). The mixture was degassed and then [1,1′-bis(diphenylphosphino)-ferrocene]-dichloropalladium(II)-complex with DCM (1:1) (39.125 mg, 0.0533 mmol) was added. The r.m. was heated overnight at 95° C. in a sealed tube. After cooling to r.t., the r.m. was filtered through diatomaceous earth. The filtrate was evaporated in vacuo. The crude residue was purified by column chromatography (silica gel; DCM as eluent). The desired fractions were collected and the solvent was evaporated in vacuo to yield a colorless oily residue that crystallized to yield D16 (0.61 g, 19.88%) as a white solid.

Description 17 5-Bromo-1-(1,4-dioxa-spiro[4.5]dec-8-yl)-1H-indole (D17)

A mixture of 5-bromoindole (8.472 g, 43.216 mmol, toluene-4-sulfonic acid 1,4-dioxa-spiro[4.5]dec-8-yl ester (13.5 g, 43.216 mmol) (prepared according to the procedure described in Journal of the Chemical Society, Perkin Transactions 1 (2002), (20), 2251-2255) and powdered potassium hydroxide (13.239 g, 235.958 mmol) in DMSO (300 ml) was stirred at 80° C. for 6 h. Subsequently, the mixture was poured into ice water. The resulting aqueous mixture was extracted with diethylether (3×), dried (Na₂SO₄), filtered and the solvent was evaporated in vacuo. The crude residue thus obtained was purified by column chromatography (silica gel; 0-10% DCM/heptane 1:1 as eluent). The desired fractions were collected and evaporated in vacuo to yield D17 (2.897 g, 19.93%) as a white solid.

Description 18 4-(5-Bromo-indol-1-yl)-cyclohexanone (D18)

A mixture of intermediate D17 (24 g, 71.38 mmol) and p-toluenesulfonic acid (0.679 mg, 3.569 mmol) in water (72 ml) and acetone (168 ml) was heated for 15 min. at 100° C. under microwave irradiation. After cooling to r.t., the r.m. was diluted with DCM and washed with a saturated aqueous NaHCO₃ solution, dried (Na₂SO₄), filtered and the solvent was evaporated in vacuo. The residue thus obtained was triturated with diethyl ether (100 ml)/acetone (30 ml). The solid was filtered off and the filtrate was evaporated in vacuo to yield D18 (18.13 g, 73%) as a yellow oil.

Description 19 4-(5-Bromo-indol-1-yl)-cyclohexanol (D19)

Sodium borohydride (62.198 mg, 1.644 mmol) was added to a stirred mixture at 0° C. of intermediate D18 (2.074 g, 7.098 mmol) in MeOH (50 ml). The resulting r.m. was warmed to r.t. and stirred for 1 h. Subsequently, the mixture was concentrated in vacuo and the residue thus obtained was dissolved in DCM. This solutions was washed with an aqueous saturated ammonium chloride solution. The organic layer was isolated, dried (Na₂SO₄), filtered and the solvent was evaporated in vacuo. The residue was purified by chromatography (silica gel; EtOAc:Heptane gradient from 0:100 to 30:70 as eluent). The desired fractions were collected and the solvent was evaporated in vacuo to yield trans-D19 (1.809 g, 86.6%) and cis-D19 (0.110 g, 5.27%).

Description 20 (Trans) trans-4-[5-(4,4,5,5-Tetramethyl-[1,3,2]dioxaborolan-2-yl)-indol-1-yl]-cyclohexanol (trans-D20)

Bis(pinacolato)diboron (0.829 g, 3.263 mmol) and potassium acetate (0.300 g, 3.059 mmol) were added to a solution of intermediate trans-D19 (0.300 g, 1.02 mmol) in dioxane (12 ml) and DMF (2 ml). The mixture was degassed and then [1,1′-bis(diphenylphosphino)-ferrocene]-dichloropalladium(ID-complex with DCM (1:1) (0.0374 g, 0.051 mmol) was added. The r.m. was heated for 1 h. at 160° C. under microwave irradiation. After cooling to r.t., the r.m. was filtered through diatomaceous earth. The filtrate was evaporated in vacuo. The residue was purified by column chromatography (silica gel; eluent: DCM/EtOAc gradient from 100:0 to 60:40). The desired fractions were collected and the solvent was evaporated in vacuo to yield trans-D20 (0.260 g, 74.6%).

Description 20 (Cis) cis-4-[5-(4,4,5,5-Tetramethyl-[1,3,2]dioxaborolan-2-yl)-indol-1-yl]-cyclohexanol (cis-D20)

Bis(pinacolato)diboron (0.265 g, 1.042 mmol) and potassium acetate (0.219 g, 2.233 mmol) were added to a solution of intermediate cis-D19 (0.219 g, 0.744 mmol) in dioxane (4 ml). The mixture was degassed and then [1,1′-bis(diphenylphosphino)-ferrocene]-dichloropalladium(II)-complex with DCM (1:1) (0.033 g, 0.045 mmol) was added. The r.m. was heated for 2 h. at 95° C. After cooling to r.t., the r.m. was filtered through diatomaceous earth. The filtrate was evaporated in vacuo. The residue was purified by column chromatography (silica gel; heptane/EtOAc gradient from 100:0 to 80:20 as eluent). The desired fractions were collected and the solvent was evaporated in vacuo to yield intermediate cis-D20 (0.213 g, 83.8%).

M.P.: 187.7° C.

Description 21 4-(5-Bromo-indol-1-yl)-1-methyl-cyclohexanol (D21)

A methylmagnesium bromide solution (1.4 M solution in toluene/THF) (3.667 ml, 5.134 mmol) was added dropwise to a cooled solution (at 0° C.) of intermediate D18 (0.5 g, 1.711 mmol) in THF (20 ml) under N₂ atmosphere. The resulting r.m. was stirred at r.t. for 4 h. After cooling in an ice bath, the mixture was carefully quenched with a saturated aqueous solution of ammonium chloride, and was subsequently extracted with DCM. The separated organic fraction was dried (Na₂SO₄), filtered and the solvent was evaporated in vacuo. The crude residue was purified by column chromatography (silica gel; 0-30% EtOAc/heptane as eluent). The desired fractions were collected and the solvent was evaporated in vacuo to yield cis-D21 (0.096 g, 18.2%) and trans-D21 (0.12 g, 22.7%).

M.P. cis-D21: 111° C.

M.P. trans-D21: 95.9° C.

Description 22 (Cis) cis-1-Methyl-4-[5-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-indol-1-yl]-cyclohexanol (cis-D22)

Bis(pinacolato)diboron (0.111 g, 0.436 mmol) and potassium acetate (0.0917 g, 0.934 mmol) were added to a solution of intermediate cis-D21 (0.096 g, 0.311 mmol) in dioxane (4 ml). The mixture was degassed and then [1,1′-bis(diphenylphosphino)-ferrocene]-dichloropalladium(II)-complex with DCM (1:1) (0.0137 g, 0.0187 mmol) was added. The r.m. was heated at 100° C. for 1.5 h. After cooling to r.t., the r.m. was filtered through diatomaceous earth. The filtrate was evaporated in vacuo. The residue was purified by column chromatography (silica gel; heptane/EtOAc gradient from 100:0 to 80:20 as eluent). The desired fractions were collected and the solvent was evaporated in vacuo to yield cis-D22 (0.074 g, 66.87%).

Description 22 (Trans) trans-1-Methyl-4-[5-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-indol-1-yl]-cyclohexanol (trans-D22)

Bis(pinacolato)diboron (0.130 g, 0.513 mmol) and potassium acetate (0.108 g, 1.1 mmol) were added to a solution of intermediate cis-D21 (0.113 g, 0.367 mmol) in dioxane (5 ml). The mixture was degassed and then [1,1′-bis(diphenylphosphino)-ferrocene]-dichloropalladium(II)-complex with DCM (1:1) (0.0161 g, 0.022 mmol) was added. The r.m. was heated at 100° C. for 2.5 h. After cooling to r.t., the r.m. was filtered through diatomaceous earth. The filtrate was evaporated in vacuo. The residue was purified by column chromatography (silica gel; heptane/EtOAc gradient from 100:0 to 80:20 as eluent). The desired fractions were collected and evaporated in vacuo to yield trans-D22 (0.096 g, 74%).

Description 23 1-Butyl-3-chloro-4-[4-(4-oxo-cyclohexyl)-3,4-dihydro-2H-benzo[1,4]oxazin-7-yl]-1H-pyridin-2-one (D23)

A mixture of intermediate D15 (0.15 g, 0.418 mmol), intermediate D4 (0.139 g, 0.418 mmol), tetrakis(triphenylphosphine)palladium(0) (0.0241 g, 0.0209 mmol) and an aqueous saturated NaHCO₃ solution (1 ml) in dioxane (4 ml), was heated at 150° C. for 10 min. under microwave irradiation. After cooling to r.t., the r.m. was filtered through diatomaceous earth, treated with EtOAc and the organic layer was washed with water and then with brine. The organic fraction was dried (Na₂SO₄), filtered and the solvent was evaporated in vacuo. The crude residue was purified by column chromatography (silica gel; 0-10% EtOAc/DCM as eluent). The desired fractions were collected and evaporated in vacuo to yield D23 (0.027 g, 15.59%).

Example 1 1-Butyl-3-chloro-4-[4-(tetrahydro-pyran-4-yl)-3,4-dihydro-2H-benzo[1,4]oxazin-7-yl]-1H-pyridin-2-one (E1);

A mixture of intermediate D16 (0.2 g, 0.348 mmol), intermediate D4 (0.116 g, 0.348 mmol), tetrakis(triphenylphosphine)palladium(0) (0.021 g, 0.0174 mmol) and an aqueous saturated NaHCO₃ solution (1 ml) in dioxane (4 ml) was heated at 150° C. for 10 min. under microwave irradiation. After cooling to r.t., the r.m. was filtered through diatomaceous earth, treated with EtOAc and the organic layer was washed first with water and subsequently with brine. The organic fraction was dried (Na₂SO₄), filtered and the solvent was evaporated in vacuo. The crude residue was purified by column chromatography (silica gel; 0-10% EtOAc/DCM as eluent) followed by reversed phase HPLC on (C18 XBridge 19×100). A gradient was applied from 80% NH₄CO₃H pH 9, and 20% CH₃CN to 0% NH₄CO₃H pH 9 and 100% CH₃CN). The desired fractions were collected and evaporated in vacuo to yield E1 (0.059 g, 41%) as a yellow solid.

M.P.: 140.7° C. ¹H NMR (400 MHz, CDCl₃) δ ppm 0.97 (t, J=7.4 Hz, 3H), 1.34-1.46 (m, 2H), 1.71-1.91 (m, 6H), 3.31-3.38 (m, 2H), 3.53 (td, J=11.7, 2.0 Hz, 2H), 3.83-3.94 (m, 1H), 3.99 (t, J=7.4 Hz, 2H), 4.11 (dd, J=11.3, 4.2 Hz, 2H), 4.22-4.29 (m, 2H), 6.19 (d, J=7.2 Hz, 1H), 6.80 (d, J=8.8 Hz, 1H), 7.00 (d, J=2.3 Hz, 1H), 7.06 (dd, J=8.6, 2.1 Hz, 1H), 7.17 (d, J=6.9 Hz, 1H).

Compound E9 was prepared in analogy to the procedure described for compound E1.

Example 2 trans-1-Butyl-3-chloro-4-[4-(4-hydroxy-cyclohexyl)-3,4-dihydro-2H-benzo[1,4]oxazin-7-yl]-1H-pyridin-2-one (E2);

Sodium borohydride (2.507 mg, 0.0663 mmol) was added to a stirred mixture of intermediate D23 (0.025 g, 0.0603 mmol) in MeOH (2 ml) at r.t. The resulting r.m. was warmed to r.t. and stirred for 1 h. Subsequently, the mixture was washed with an aqueous saturated NaHCO₃ solution and extracted with DCM. The separated organic layer was collected, dried (Na₂SO₄), filtered and the solvent was evaporated in vacuo. The residue was triturated with DIPE to yield E2 (20 mg) as a white solid.

M.P.: 178° C. ¹H NMR (400 MHz, C₆D₆) δ ppm 0.84 (t, J=7.3 Hz, 3H), 1.00-1.12 (m, 2H), 1.10-1.20 (m, 2H), 1.20-1.32 (m, 2H), 1.42 (br. s., 1H), 1.48-1.58 (m, 4H), 1.81-1.92 (m, 2H), 2.68-2.78 (m, 2H), 3.26-3.35 (m, 1H), 3.35-3.45 (m, 1H), 3.61 (t, J=7.4 Hz, 2H), 3.85-3.91 (m, 2H), 5.96 (d, J=6.9 Hz, 1H), 6.28 (d, J=6.9 Hz, 1H), 6.69 (d, J=8.8 Hz, 1H), 7.36 (dd, J=8.4, 2.2 Hz, 1H), 7.43 (d, J=2.1 Hz, 1H).

Example 3 trans-1-Butyl-3-chloro-4-[1-(4-hydroxy-cyclohexyl)-1H-indol-5-yl]-1H-pyridin-2-one (E3);

A mixture of intermediate trans-D20 (1 g, 2.93 mmol), intermediate D4 (0.815 g, 2.442 mmol), tetrakis(triphenylphosphine)palladium(0) (0.141 g, 0.122 mmol) and an aqueous saturated NaHCO₃ solution (4 ml) in dioxane (12 ml) was heated at 150° C. for 7 min. under microwave irradiation. After cooling to r.t., the r.m. was filtered through diatomaceous earth, treated with EtOAc and the organic layer was first washed with water and then with brine. The organic fraction was dried (Na₂SO₄), filtered and the solvent was evaporated in vacuo. The crude residue was purified by column chromatography (silica gel; 0-10% heptane/EtOAc as eluent). The desired fractions were collected and evaporated in vacuo. The residue was triturated with diethyl ether. The white precipitate obtained was filtered off and dried in vacuo to yield E3 (0.506 g, 52%) as a white solid.

M.P.: 191.1° C. ¹H NMR (500 MHz, CDCl₃) δ ppm 0.99 (t, J=7.4 Hz, 3H), 1.37-1.48 (m, 2H), 1.53-1.66 (m, 3H), 1.77-1.85 (m, 2H), 1.82-1.93 (m, 2H), 2.19 (br d, J=12.4 Hz, 4H), 3.74-3.88 (m, 1H), 4.03 (t, J=7.4 Hz, 2H), 4.21-4.36 (m, 1H), 6.29 (d, J=6.9 Hz, 1H), 6.57 (d, J=3.2 Hz, 1H), 7.22 (d, J=6.9 Hz, 1H), 7.24 (d, J=3.2 Hz, 1H), 7.35 (dd, J=8.5, 1.6 Hz, 1H), 7.44 (d, J=8.4 Hz, 1H), 7.75 (d, J=1.4 Hz, 1H).

Example 4 cis-1-Butyl-3-chloro-4-[1-(4-hydroxy-cyclohexyl)-1H-indol-5-yl]-1H-pyridin-2-one (E4);

A mixture of intermediate cis-D20 (0.144 g, 0.422 mmol), intermediate D4 (0.117 g, 0.352 mmol), tetrakis(triphenylphosphine)palladium(0) (0.020 g, 0.0176 mmol) and an aqueous saturated NaHCO₃ solution (1 ml) in dioxane (3 ml) was heated at 150° C. for 7 min. under microwave irradiation. After cooling to r.t., the r.m. was filtered through diatomaceous earth, treated with EtOAc and the organic layer was first washed with water and subsequently with brine. The organic fraction was dried (Na₂SO₄), filtered and the solvent was evaporated in vacuo. The crude residue was purified by column chromatography (silica gel; heptane/EtOAc from 100:0 to 30:70 as eluent). The desired fractions were collected and evaporated in vacuo. The residue thus obtained was triturated with DIPE. The white precipitate obtained was filtered off and dried in vacuo to yield E4 (0.077 g, 54%) as a white solid.

M.P.: 280.7° C. ¹H NMR, (500 MHz, CDCl₃) δ ppm 0.99 (t, J=7.4 Hz, 3H), 1.37 (br. s., 1H), 1.38-1.49 (m, 2H), 1.70-1.88 (m, 4H), 1.95 (br d, J=11.9 Hz, 2H), 2.02 (br d, J=14.7 Hz, 2H), 2.26 (qd, J=12.7, 2.9 Hz, 2H), 4.03 (t, J=7.2 Hz, 2H), 4.21 (br. s., 1 H), 4.24-4.35 (m, 1H), 6.30 (d, J=6.9 Hz, 1H), 6.58 (d, J=2.9 Hz, 1H), 7.22 (d, J=7.2 Hz, 1H), 7.30-7.39 (m, 2H), 7.45 (d, J=8.7 Hz, 1H), 7.75 (br. s., 1H).

Example 5 trans-1-Butyl-3-chloro-4-[1-(4-hydroxy-4-methyl-cyclohexyl)-1H-indol-5-yl]-1H-pyridin-2-one (E5);

A mixture of intermediate trans-D22 (0.0964 g, 0.271 mmol), D4 (0.082 g, 0.247 mmol), tetrakis(triphenylphosphine)palladium(0) (0.020 g, 0.0176 mmol) and a saturated aqueous NaHCO₃ solution (1 ml) in dioxane (3 ml) was heated at 150° C. for 7 min. under microwave irradiation. After cooling to r.t., the r.m. was filtered through diatomaceous earth, treated with EtOAc and the organic layer was washed with water and brine. The organic fraction was dried (Na₂SO₄), filtered and the solvent was evaporated in vacuo. The crude residue was purified by column chromatography (silica gel; heptane/EtOAc from 100:0 to 30:70 as eluent). The desired fractions were collected and the solvent was evaporated in vacuo. The residue thus obtained was triturated with diethyl ether. The white precipitate obtained was filtered off and dried in vacuo to yield E5 (0.545 g, 53.5%) as a white solid. ¹H NMR (500 MHz, CDCl₃) δ ppm 0.99 (t, J=7.2 Hz, 3H) 1.13 (s, 1H) 1.35 (s, 3H) 1.38-1.47 (m, 2H) 1.68 (td, J=13.7, 3.8 Hz, 2H) 1.78-1.84 (m, 2H) 1.87 (br d, J=13.0 Hz, 2H) 1.97 (br d, J=12.4 Hz, 2H) 2.23 (qd, J=12.8, 3.5 Hz, 2H) 4.02 (t, J=7.4 Hz, 2H) 4.24 (tt, J=12.1, 3.7 Hz, 1H) 6.29 (d, J=6.9 Hz, 1H) 6.57 (d, J=2.9 Hz, 1H) 7.22 (d, J=7.2 Hz, 1H) 7.31-7.37 (m, 2H) 7.44 (d, J=8.7 Hz, 1H) 7.75 (d, J=0.9 Hz, 1H).

Example 6 cis-1-Butyl-3-chloro-4-[1-(4-hydroxy-4-methyl-cyclohexyl)-1H-indol-5-yl]-1H-pyridin-2-one (E6);

A mixture of intermediate cis-D22 (0.074 g, 0.208 mmol), intermediate D4 (0.063 g, 0.189 mmol), tetrakis(triphenylphosphine)palladium(0) (0.011 g, 0.0095 mmol) and a saturated aqueous NaHCO₃ solution (1 ml) in dioxane (3 ml) was heated at 150° C. for 7 min. under microwave irradiation. After cooling to r.t., the r.m. was filtered through diatomaceous earth, treated with EtOAc and the organic layer was washed with water and brine. The organic fraction was dried (Na₂SO₄), filtered and the solvent was evaporated in vacuo. The crude residue was purified by column chromatography (silica gel; heptane/EtOAc from 100:0 to 30:70 as eluent). The desired fractions were collected and evaporated in vacuo. The residue thus obtained was triturated with diethyl ether. The white precipitate obtained was filtered off and dried in vacuo to yield E5 (0.54 g, 69.5%) as a white solid. ¹H NMR (400 MHz, CDCl₃) δ ppm 0.99 (t, J=7.4 Hz, 3H), 1.36-1.49 (m, 3H), 1.43 (s, 3H), 1.72-1.86 (m, 4H), 1.86-2.00 (m, 4H), 2.07-2.23 (m, 2H), 4.03 (t, J=7.3 Hz, 2H), 4.25-4.40 (m, 1H), 6.29 (d, J=6.9 Hz, 1H), 6.58 (d, J=3.2 Hz, 1H), 7.22 (d, J=7.2 Hz, 1H), 7.27 (d, J=3.5 Hz, 1H), 7.35 (dd, J=8.6, 1. Hz, 1H), 7.43 (d, J=8.8 Hz, 1H), 7.75 (d, J=1.2 Hz, 1H).

Example 7 trans-3-Chloro-4-[1-(4-hydroxy-cyclohexyl)-1H-indol-5-yl]-1-(3-methyl-butyl)-1H-pyridin-2-one (E7);

A mixture of intermediate trans-D20 (0.294 g, 0.863 mmol), intermediate D5 (0.25 g, 0.719 mmol), tetrakis(triphenylphosphine)palladium(0) (0.0415 g, 0.0359 mmol) and an aqueous saturated NaHCO₃ solution (2 ml) in dioxane (6 ml) was heated at 150° C. for 7 min. under microwave irradiation. After cooling to r.t., the r.m. was filtered through diatomaceous earth, treated with EtOAc and the organic layer was washed with water and brine. The organic fraction was dried (Na₂SO₄), filtered and the solvent was evaporated in vacuo. The crude residue was purified by column chromatography (silica gel; 0-20% MeOH/DCM as eluent). The desired fractions were collected and the solvent was evaporated in vacuo. The residue was triturated with diethyl ether. The white precipitate was filtered off and dried in vacuo. Yield: 0.175 g of compound E7 (59%) as a white solid.

M.P. 182.3° C. ¹H NMR (400 MHz, CDCl₃) δ ppm 1.00 (d, J=6.0 Hz, 6H), 1.52-1.65 (m, 3H), 1.66-1.77 (m, 3H), 1.78-1.96 (m, 2H), 2.20 (br d, J=11.1 Hz, 4H), 3.71-3.89 (m, 1H), 3.96-4.11 (m, 2H), 4.21-4.37 (m, 1H), 6.29 (d, J=6.9 Hz, 1H), 6.57 (d, J=3.2 Hz, 1H), 7.20-7.25 (m, 2H), 7.34 (dd, J=8.5, 1.4 Hz, 1H), 7.43 (d, J=8.6 Hz, 1H), 7.70-7.78 (m, 1H).

Example 8 trans-3-Chloro-1-cyclopropylmethyl-4-[1-(4-hydroxy-cyclohexyl)-1H-indol-5-yl]-1H-pyridin-2-one (E8);

A mixture of intermediate trans-D20 (0.308 g, 0.904 mmol), intermediate D6 (0.250 g, 0.754 mmol), tetrakis(triphenylphosphine)palladium(0) (0.0435 g, 0.0377 mmol) and a saturated aqueous NaHCO₃ solution (2 ml) in dioxane (6 ml) was heated at 150° C. for 7 min. under microwave irradiation. After cooling to r.t., the r.m. was filtered through diatomaceous earth, treated with EtOAc and the organic layer was washed with water and brine. The organic fraction was dried (Na₂SO₄), filtered and the solvent was evaporated in vacuo. The crude residue was purified by column chromatography (silica gel; 0-20% MeOH/DCM as eluent). The desired fractions were collected and evaporated in vacuo. The residue was triturated with diethyl ether. The white precipitate obtained was filtered off and dried in vacuo to yield E8 (0.506 g, 52%) as a white solid.

M.P.=209.4° C. ¹H NMR (400 MHz, CDCl₃) δ ppm 0.39-0.50 (m, 2H), 0.59-0.73 (m, 2H), 1.29-1.38 (m, 1H), 1.48-1.70 (m, 3H), 1.77-1.97 (m, 2H), 2.20 (br d, J=11.1 Hz, 4H), 3.76-3.87 (m, 1H), 3.90 (d, J=7.2 Hz, 2H), 4.20-4.38 (m, 1H), 6.32 (d, J=7.2 Hz, 1H), 6.58 (d, J=3.2 Hz, 1H), 7.24 (d, J=3.5 Hz, 1H), 7.32-7.38 (m, 2H), 7.44 (d, J=8.8 Hz, 1H), 7.76 (d, J=0.9 Hz, 1H).

Physico-Chemical Data LCMS—General Procedure

The HPLC measurement was performed using a HP 1100 from Agilent Technologies comprising a pump (quaternary or binary) with degasser, an autosampler, a column oven, a diode-array detector (DAD) and a column as specified in the respective methods below. Flow from the column was split to a MS spectrometer. The MS detector was configured with either an electrospray ionization source or an ESCI dual ionization source (electrospray combined with atmospheric pressure chemical ionization). Nitrogen was used as the nebulizer gas. The source temperature was maintained at 140° C. Data acquisition was performed with MassLynx-Openlynx software.

Method 1: This method was used for example E3 and E9

In addition to the general procedure: Reversed phase HPLC was carried out on an XDB-C18 cartridge (1.8 μm, 2.1×30 mm) from Agilent, at 60° C. with a flow rate of 1 ml/min, at 60° C. The gradient conditions used are: 90% A (0.5 g/l ammonium acetate solution), 5% B (CH₃CN), 5% C (MeOH) to 50% B and 50% C in 6.5 min., to 100% B at 7 min. and equilibrated to initial conditions at 7.5 min. until 9.0 min. Injection volume 2 μl. High-resolution mass spectra (Time of Flight, TOF) were acquired by scanning from 100 to 750 in 0.5 s. using a dwell time of 0.3 s (E3) or 0.1 s (E9). The capillary needle voltage was 2.5 kV for positive ionization mode and 2.9 kV for negative ionization mode. The cone voltage was 20 V for both positive and negative ionization modes. Leucine-Enkephaline was the standard substance used for the lock mass calibration.

Method 2: This method was used for example E1, E2,E7 and E8

In addition to the general procedure: Reversed phase HPLC was carried out on a BEH-C18 column (1.7 μm, 2.1×50 mm) from Waters, with a flow rate of 0.8 ml/min, at 60° C. without split to the MS detector. The gradient conditions used are: 95% A (0.5 g/l ammonium acetate solution+5% CH₃CN), 5% B (mixture of CH₃CN/MeOH, 1/1), to 20% A, 80% B in 4.9 min., to 100% B in 5.3 min., kept till 5.8 min. and equilibrated to initial conditions at 6.0 min. until 7.0 min. Injection volume 0.5 μl. Low-resolution mass spectra (SQD detector; quadrupole) were acquired by scanning from 100 to 1000 in 0.1 s. using an inter-channel delay of 0.08 s. The capillary needle voltage was 3 kV. The cone voltage was 20 V for positive ionization mode and 30 V for negative ionization mode.

Method 3: This method was used for example E4

In addition to the general procedure: Reversed phase HPLC was carried out on a Sunfire-C18 column (2.5 μm, 2.1×30 mm) from Waters, with a flow rate of 1.0 ml/min, at 60° C. The gradient conditions used are: 95% A (0.5 g/l ammonium acetate solution+5% of CH₃CN), 2.5% B (CH₃CN), 2.5% C (MeOH) to 50% B and 50% C in 6.5 minutes, kept till 7 min. and equilibrated to initial conditions at 7.3 min. until 9.0 min. Injection volume 2 μl. High-resolution mass spectra (Time of Flight, TOF) were acquired by scanning from 100 to 750 in 0.5 s. using a dwell time of 0.3 s. The capillary needle voltage was 2.5 kV for positive ionization mode and 2.9 kV for negative ionization mode. The cone voltage was 20 V for both positive and negative ionization modes. Leucine-Enkephaline was the standard substance used for the lock mass calibration.

Method 4: This method was used for example E5 and E6

In addition to the general procedure: Reversed phase HPLC was carried out on a Sunfire-C18 column (2.5 μm, 2.1×30 mm) from Waters, with a flow rate of 1.0 ml/min, at 60° C. The gradient conditions used are: 95% A (0.5 g/l ammonium acetate solution+5% CH₃CN), 5% B (mixture of CH₃CN/MeOH, 1/1), to 100% B in 5.0 minutes, kept till 5.15 min. and equilibrated to initial conditions at 5.3 min. until 7.0 min. Injection volume 2 μl. Low-resolution mass spectra (Quadrupole, MSD) were acquired in electrospray mode by scanning from 100 to 1000 in 0.99 s., step size of 0.30 and peak width of 0.10 min. The capillary needle voltage was 1.0 kV and the fragmentor voltage was 70 V for both positive and negative ionization modes.

Melting Points

For a number of compounds, melting points were determined in open capillary tubes on a Mettler FP62 apparatus. Melting points were measured with a temperature gradient of 3 or 10° C./min. Maximum temperature was 300° C. The M.P. was read from a digital display and were obtained with experimental uncertainties that are commonly associated with this analytical method.

Nuclear Magnetic Resonance (NMR)

¹H NMR spectra were recorded on a Bruker DPX-400 and on a Bruker AV-500 spectrometer with standard pulse sequences, operating at 400 MHz and 500 MHz respectively, using CDCL₃ and C₆D₆ as solvents. Chemical shifts (δ) are reported in parts per million (ppm) downfield from tetramethylsilane (TMS), which was used as internal standard.

Table 1 lists compounds of Formula (I) that were prepared according to one of the above Examples (Ex. No.). RT means retention time (in minutes).

TABLE 1

Ex. Melting RT No. R¹ X n Y Point (° C.) MH⁺ (min) E1

—CH₂CH₂O— 2 —O— 140.7 403 3.40 E2

—CH₂CH₂O— 2

178.0 417 3.17 E3

—CH═CH— 2

191.1 399 4.10 E4

—CH═CH— 2

280.7 399 4.40 E5

—CH═CH— 2

decomposed 413 3.63 E6

—CH═CH— 2

decomposed 413 3.98 E7

—CH═CH— 2

182.3 413 3.60 E8

—CH═CH— 2

209.4 397 3.05 E9

—CH═CH— 2 —O— n.d. 385 4.29 n.d.: not determined

Pharmacological Examples

The compounds provided in the present invention are positive allosteric modulators of mGluR2. These compounds appear to potentiate glutamate responses by binding to an allosteric site other than the glutamate binding site. The response of mGluR2 to a concentration of glutamate is increased when compounds of Formula (I) are present. Compounds of Formula (I) are expected to have their effect substantially at mGluR2 by virtue of their ability to enhance the function of the receptor. The behaviour of positive allosteric modulators tested at mGluR2 using the [³⁵S]GTPγS binding assay method described below and which is suitable for the identification of such compounds, and more particularly the compounds according to Formula (I), are shown in Table 4.

[³⁵S] GTPγS Binding Assay

The [³⁵S]GTPγS binding assay is a functional membrane-based assay used to study G-protein coupled receptor (GPCR) function whereby incorporation of a non-hydrolysable form of GTP, [³⁵S]GTPγS (guanosine 5′-triphosphate, labelled with gamma-emitting ³⁵S), is measured. The G-protein α subunit catalyzes the exchange of guanosine 5′-diphosphate (GDP) by guanosine triphosphate (GTP) and on activation of the GPCR by an agonist, [³⁵S]GTPγS, becomes incorporated and cannot be cleaved to continue the exchange cycle (Harper (1998) Current Protocols in Pharmacology 2.6.1-10, John Wiley & Sons, Inc.). The amount of radioactive [³⁵S]GTPγS incorporation is a direct measure of the activity of the G-protein and hence the activity of the agonist can be determined. mGluR2 receptors are shown to be preferentially coupled to Gαi-protein, a preferential coupling for this method, and hence it is widely used to study receptor activation of mGluR2 receptors both in recombinant cell lines and in tissues (Schaffhauser et al 2003, Pinkerton et al, 2004, Mutel et al (1998) Journal of Neurochemistry. 71:2558-64; Schaffhauser et al (1998) Molecular Pharmacology 53:228-33). Here we describe the use of the [³⁵S]GTPγS binding assay using membranes from cells transfected with the human mGluR2 receptor and adapted from Schaffhauser et al ((2003) Molecular Pharmacology 4:798-810) for the detection of the positive allosteric modulation (PAM) properties of the compounds of this invention.

Membrane Preparation

CHO-cells were cultured to pre-confluence and stimulated with 5 mM butyrate for 24 hours, prior to washing in PBS (phosphate-buffered saline), and then collection by scraping in homogenisation buffer (50 mM Tris-HCl buffer, pH 7.4, 4° C.). Cell lysates were homogenized briefly (15 s) using an ultra-turrax homogenizer. The homogenate was centrifuged at 23 500×g for 10 min. and the supernatant discarded. The pellet was resuspended in 5 mM Tris-HCl, pH 7.4 and centrifuged again (30 000×g, 20 min., 4° C.). The final pellet was resuspended in 50 mM HEPES, pH 7.4 and stored at −80° C. in appropriate aliquots before use. Protein concentration was determined by the Bradford method (Bio-Rad, USA) with bovine serum albumin as standard.

[³⁵S] GTPγS Binding Assay

Measurement of mGluR2 positive allosteric modulatory activity of test compounds in membranes containing human mGluR2 was performed using frozen membranes that were thawed and briefly homogenised prior to pre-incubation in 96-well microplates (15 μg/assay well, 30 minutes, 30° C.) in assay buffer (50 mM HEPES pH 7.4, 100 mM NaCl, 3 mM MgCl₂, 50 μM GDP, 10 μg/ml saponin) with increasing concentrations of positive allosteric modulator (from 0.3 nM to 50 μM) and either a minimal pre-determined concentration of glutamate (PAM assay), or no added glutamate. For the PAM assay, membranes were pre-incubated with glutamate at EC₂₅ concentration, i.e. a concentration that gives 25% of the maximal response glutamate, and is in accordance to published data (Pin et al. (1999) Eur. J. Pharmacol. 375:277-294). After addition of [³⁵S]GTPγS (0.1 nM, f.c.) to achieve a total reaction volume of 200 μl, microplates were shaken briefly and further incubated to allow [³⁵S]GTPγS incorporation on activation (30 minutes, 30° C.). The reaction was stopped by rapid vacuum filtration over glass-fibre filter plates (Unifilter 96-well GF/B filter plates, Perkin-Elmer, Downers Grove, USA) microplate using a 96-well plate cell harvester (Filtermate, Perkin-Elmer, USA), and then by washing three times with 300 μl of ice-cold wash buffer (Na₂PO₄.2H₂O 10 mM, NaH₂PO₄.H₂O 10 mM, pH=7.4). Filters were then air-dried, and 40 μl of liquid scintillation cocktail (Microscint-O) was added to each well, and membrane-bound [³⁵S]GTPγS was measured in a 96-well scintillation plate reader (Top-Count, Perkin-Elmer, USA). Non-specific [³⁵S]GTPγS binding is determined in the presence of cold 10 μM GTP. Each curve was performed at least once using duplicate sample per data point and at 11 concentrations.

Data Analysis

The concentration-response curves of representative compounds of the present invention in the presence of added EC₂₅ of mGluR2 agonist glutamate to determine positive allosteric modulation (PAM), were generated using the Prism GraphPad software (Graph Pad Inc, San Diego, USA). The curves were fitted to a four-parameter logistic equation (Y=Bottom+(Top-Bottom)/(1+10̂((Log EC₅₀−X)*Hill Slope) allowing determination of EC₅₀ values. The EC₅₀ is the concentration of a compound that causes a half-maximal potentiation of the glutamate response. This was calculated by subtracting the maximal responses of glutamate in presence of a fully saturating concentration of a positive allosteric modulator from the response of glutamate in absence of a positive allosteric modulator. The concentration producing the half-maximal effect was then calculated as EC₅₀.

TABLE 2 Pharmacological data for compounds according to the invention. Comp. No. GTPgS-hR2 PAM pEC₅₀ 1 6.23 2 n.d. 3 6.99 4 6.83 5 7.12 6 6.52 7 7.05 8 6.52 9 6.51 All compounds were tested in presence of mGluR2 agonist, glutamate at a predetermined EC₂₅ concentration, to determine positive allosteric modulation (GTPγS-PAM). Values shown are averages of duplicate values of 11-concentration response curves, from at least one experiment. All tested compounds showed a pEC₅₀ (-logEC₅₀) value of more than 5.0, from 6.23 (weak activity) to 7.05 (very high activity). The error of determination of a pEC₅₀ value for a single experiment is estimated to be about 0.3 log-units. n.d. = not determined

Composition Examples

“Active ingredient” as used throughout these examples relates to a final compound of formula (I), the pharmaceutically acceptable salts thereof, the solvates and the stereochemically isomeric forms thereof.

Typical examples of recipes for the formulation of the invention are as follows:

1. Tablets

Active ingredient 5 to 50 mg Di-calcium phosphate 20 mg Lactose 30 mg Talcum 10 mg Magnesium stearate 5 mg Potato starch ad 200 mg

In this Example, active ingredient can be replaced with the same amount of any of the compounds according to the present invention, in particular by the same amount of any of the exemplified compounds.

2. Suspension

An aqueous suspension is prepared for oral administration so that each 1 milliliter contains 1 to 5 mg of one of the active compounds, 50 mg of sodium carboxymethyl cellulose, 1 mg of sodium benzoate, 500 mg of sorbitol and water ad 1 ml.

3. Injectable

A parenteral composition is prepared by stirring 1.5% by weight of active ingredient of the invention in 10% by volume propylene glycol in water.

4. Ointment

Active ingredient 5 to 1000 mg Stearyl alcohol 3 g Lanoline 5 g White petroleum 15 g Water ad 100 g

In this Example, active ingredient can be replaced with the same amount of any of the compounds according to the present invention, in particular by the same amount of any of the exemplified compounds.

Reasonable variations are not to be regarded as a departure from the scope of the invention. It will be obvious that the thus described invention may be varied in many ways by those skilled in the art. 

1. A compound having the formula (I)

or a stereochemically isomeric form thereof, wherein R¹ is C₁₋₆alkyl; or C₁₋₃alkyl substituted with C₃₋₇cycloalkyl, halo, phenyl, or phenyl substituted with halo, trifluoromethyl or trifluoromethoxy; R² is halo, trifluoromethyl, C₁₋₃alkyl or cyclopropyl; R³ is hydrogen, halo or trifluoromethyl; n is 1 or 2; X is —CH₂CH₂—O, —CH═CH—, or —CH₂CH₂—; Y is —O— or —CR⁴(OH)—; R⁴ is hydrogen or C₁₋₃alkyl; or a pharmaceutically acceptable salt or a solvate thereof.
 2. The compound according to claim 1 wherein R¹ is C₁₋₆alkyl; or C₁₋₃alkyl substituted with C₃₋₇cycloalkyl, phenyl, or phenyl substituted with halo, trifluoromethyl or trifluoromethoxy; R² is halo, trifluoromethyl, C₁₋₃alkyl or cyclopropyl; R³ is hydrogen, halo or trifluoromethyl; n is 1 or 2; X is —CH₂CH₂—O—, —CH═CH—, or —CH₂CH₂—; Y is —O— or —CR⁴(OH)—; R⁴ is hydrogen or C₁₋₃alkyl; or a pharmaceutically acceptable salt or a solvate thereof.
 3. The compound according to claim 1 wherein R¹ is 1-butyl, 2-methyl-1-propyl, 3-methyl-1-butyl, (cyclopropyl)methyl or 2-(cyclopropyl)-1-ethyl; R² is chloro, bromo, cyclopropyl or trifluoromethyl; R³ is hydrogen orchloro or trifluoromethyl; n is 2; X is —CH₂CH₂—O— or —CH═CH—; Y is —O— or —CR⁴(OH)—; R⁴ is hydrogen or C₁₋₃alkyl; or a pharmaceutically acceptable salt or a solvate thereof.
 4. The compound according to claim 1 wherein said compound is trans-1-Butyl-3-chloro-4-[1-(4-hydroxy-cyclohexyl)-1H-indol-5-yl]-1H-pyridin-2-one (E3), or trans-1-Butyl-3-chloro-4-[1-(4-hydroxy-4-methyl-cyclohexyl)-1H-indol-5-yl]-1H-pyridin-2-one (E5).
 5. A pharmaceutical composition comprising a therapeutically effective amount of a compound according to any one of claims 1 to 4 and a pharmaceutically acceptable carrier or excipient.
 6. A compound according to any one of claims 1 to 4 for use as a medicament.
 7. A compound according to any one of claims 1 to 4 or a pharmaceutical composition according to claim 5 for use in the treatment or prevention of a disease or a condition in a mammal, including a human, the treatment or prevention of which is affected or facilitated by the neuromodulatory effect of mGluR2 positive allosteric modulators.
 8. A compound according to any one of claims 1 to 4 or a pharmaceutical composition according to claim 5 for use in the treatment or prevention of a central nervous system disorder selected from the group of anxiety disorders, psychotic disorders, personality disorders, substance-related disorders, eating disorders, mood disorders, migraine, epilepsy or convulsive disorders, childhood disorders, cognitive disorders, neurodegeneration, neurotoxicity and ischemia.
 9. The compound or the pharmaceutical composition according to claim 8, wherein the central nervous system disorder is an anxiety disorder, selected from the group of agoraphobia, generalized anxiety disorder (GAD), obsessive-compulsive disorder (OCD), panic disorder, posttraumatic stress disorder (PTSD), social phobia and other phobias.
 10. The compound or the pharmaceutical composition according to claim 8, wherein the central nervous system disorder is a psychotic disorder selected from the group of schizophrenia, delusional disorder, schizoaffective disorder, schizophreniform disorder and substance-induced psychotic disorder.
 11. The compound or the pharmaceutical composition according to claim 8, wherein the central nervous system disorder is a mood disorder selected from the group of bipolar disorders (I & II), cyclothymic disorder, depression, dysthymic disorder, major depressive disorder and substance-induced mood disorder.
 12. The compound or the pharmaceutical composition according to claim 8, wherein the central nervous system disorder is epilepsy or a convulsive disorder selected from the group of generalized nonconvulsive epilepsy, generalized convulsive epilepsy, petit mal status epilepticus, grand mal status epilepticus, partial epilepsy with or without impairment of consciousness, infantile spasms, epilepsy partialis continua, and other forms of epilepsy.
 13. The compound or the pharmaceutical composition according to claim 8, wherein the childhood disorder is attention-deficit/hyperactivity disorder.
 14. The compound or the pharmaceutical composition according to claim 8, wherein the central nervous system disorder is a cognitive disorder selected from the group of delirium, substance-induced persisting delirium, dementia, dementia due to HIV disease, dementia due to Huntington's disease, dementia due to Parkinson's disease, dementia of the Alzheimer's type, substance-induced persisting dementia and mild cognitive impairment.
 15. A compound according to any one of claims 1 to 4 and an orthosteric agonist of mGluR2 as a combined preparation for simultaneous, separate or sequential use in the treatment or prevention of a condition as cited in any one of claims 7 to
 14. 16. A method of treating or preventing a disease or a condition in a patient, the treatment or prevention of which is affected or facilitated by the neuromodulatory effect of mGluR2 positive allosteric modulators comprising administering to a patient in need thereof an effective amount of a compound according to any one of claims 1 to
 4. 